I bought a Trek 8.3 DS and do love it. I'm putting about 5-9 miles, every two days on it.

If you've read my previous posts about me, skip this whole paragraph: I'm 51, recently went from 365 to 225lbs and haven't ridden since gas was .55 a gallon and all the cool cars had CB's. I need to add activity to my life and even though I have a completely destroyed back (multiple surgeries) and lots of nerve problems in my legs, I'm going to ride.

Further (about where I live), I live in a VERY hilly environment on the ridge of the foothills leading to the Sierra Nevada mountains. I live at 1825', while my town goes from 1100 to nearly 2500' - in about six miles. There is a central bike trail (from train to trail conversion) running through the center of town (basically, up and down). I started at about 2.4 miles last month and have built up to around 5-9 miles, with 400-600' elevation gains. The trail is paved, but we have extreme weather conditions and that means the trail (and the town) get the crap kicked out of it. We just endured 42" of rain in seven days. Our yearly average is 59".

So, I got the LR2 tires with the bike - 700cx38. They are 60psi tires. While they are a LOT easier to ride than the MTB tires, I'd still like to have a tire with a bit less rolling resistance. I would like something with more puncture protection, as well. I had Schwable Big Apples on my 'bent trike, and I liked the brand. Though obviously not considering BA's!

Once I start looking, there are just tons of choices. I was thinking something like the Marathon Plus or GG's in same size. I'm wondering if others have used these on hybrids and what their experiences were.

On a separate note, I'm also wondering about tubeless. I keep seeing 'kits' to do this and they are over $200! Should I go with a kit or just get dedicated wheel/tire combinations that are tubeless designated?

What I'm trying to achieve is less rolling resistance, good traction on pine needles and leaves and puncture resistance. I'd also love to keep some ability to use a dirt trail if the opportunity presents itself.

Or am I looking for the impossible?

There are trade offs.
Hard packed dirt and a very minimal tread will suffice. A bit looser dirt or pine needles/leaves and you're in a totally different ball game.

For pavement I like Vittoria Randonneur Hyper. I use 700x38c but they come in 700x32 & 35c as well. Low drag, highly puncture resistant and fast.

+1

I have the Vittoria Hyper in both the 700x38 and the 700x32 size. The 700x32 measure out to 34mm wide on a 23mm wide rim. It is a good size for most of my riding. The tire is very stable with great traction on pavement and gravel. Wet gravel causes no issues, but wet mud and wet silty soil can be a problem. I just ride carefully on off-camber turns if the ground is wet.

The tire is light but tough. It will make climbing easier without a doubt.

Another issue to consider is the front suspension fork on your Trek. You might notice some travel (the fork going up and down) as you pedal. The fork is reducing the power going to the rear wheel when that happens.

Be sure to use the lock-out feature on your fork when climbing. This will make the climb easier.

I was down at the LBS and they had a pair of the Randonneur Hyper x38's on the shelf, which I noted were labeled 40-622 even tho they also said 700x38. this usually means the tire runs slightly oversize. I decided to go ahead and order the x35 size, and will report in when they get here and when I get them mounted.

Big Apples wouldn't be bad really. Even though they are bigger and heavier, they don't necessarily have more rolling resistance and they may have less due to the tread pattern compared to your current tires. Maybe something like the Schwalbe Sillento or one of the Marathon tires would work for you.

It is important to note the distinction between rolling resistance and inertia. Rolling resistance is friction or drag resisting the rolling motion. Inertia is the resistance to change in state of motion. An object at rest wants to stay at rest and moving (or rotating) object wants to keep moving. When accelerating, bigger and heavier tires feel harder to roll because they are more difficult to accelerate, but this is due to inertia, not rolling resistance. Once up to speed, the power to keep the bike going is significantly less than that of accelerating it. The rolling tire wants to keep rolling if you keep the speed about the same.

Don't be too tempted to go narrower. A narrower tire doesn't necessarily have less rolling resistance and may in fact have more because the tire deforms more and becomes less round than a wider tire. This is assuming you are comparing similar tires. Assuming the same pressure, the wider tire deforms more in the width and less in the circumference so it stays more round than a narrower tire. I remember one guy here keeps swearing up and down that narrower tires have lower rolling resistance, but then I found out he was comparing knobby CX 38 or 25 to smooth 28 for street...It's only once you're up to about 20MPH where narrower tires start to become beneficial because aerodynamic drag becomes a bigger issue. On a Trek DS though, this isn't a huge concern because the upright riding position compared to road bikes will be a much bigger factor than the tire.

This

And tire performance with minimal tread just gets worse offroad in wet conditions. If you really have to deal with both paved sunny roads and wet offroad trails seriously suggest you consider two sets of wheels and different tires on each so you can pick and choose.

except narrower tires inherently use higher pressures. a 25c tire probably has 110-120psi in it, while a 35c hybrid tire is more like 60-80psi. if the same weight rider put 60psi in that 25c, they'd pinch flat the first time they hit a crack in the pavement.

Since I'm keeping the LT2's at 60 - which is what they are rated for - and they seem to flatten out more than a bit under my load, should I be considering a higher pressure tire? Should they 'flatten out' under my 225lbs?

I keep seeing that people consider tires to be a good upgrade. I changed my bars to the Iso-zone model and those helped a bit in the hand numb category. I changed out my pedals for Wellgo B-67's and I like the extra room they give. I added a Selle saddle and finally can make it 6-7 miles before pain sets in. I'm just thinking that new tires - especially ones with a little higher pressure, would add that reduction in rolling resistance.

Please keep in mind I'm totally new to this and so am not arguing against advice, rather my questions are for clarification.

Next I'm gonna be asking about IGH's... Alfine 8 or 11?

and actually, I got said Hyper Randonneurs in x32, which pumped to 70psi measure 33mm on my 1" wide OD rims. and they go like grease compared with the Nimbus my bike came with! felt like I was flying up the small hills on my 15 mile loop yesterday. https://goo.gl/maps/1uA1s

Get a set of Schwalbe Marathon Supremes, and run 'em at 92PSI. You will be amazed at the difference.