Okay... so I am ready to try and use my bike for everyday utilitarian tasks like shopping etc.
BUT... here where I live there are hills, lots of hills, steep hills!
So, how hard is it to pedal a bike up a steep hill with a trailer loaded with a weeks worth of groceries?
I commute to work up these same hills 11 miles (each way) three or four days a week with a rack and single pannier, loaded with clothes and lunch for the day.
The bike I use is a Trek 7.5FX, with some upgraded components.
The trailer I am looking at is the Burley Flatbed or Nomad.
Any advice, experience, or opinions are much appreciated.

I have small child trailer (Instep Quick and easy) attached to my Giant Cypress which I haul groceries around in. My commute is around 11-12 miles round trip with a few hills and I have no problems with about a 30lb load. I suppose if I really loaded up to about 75-80lbs I may have to take a break.

There are no hills you cannot get up pulling a loaded trailer if you have low enough gears. A friend went up Fargo Street in LA pulling his son in a Burley cart. 33% grade and the sidewalks were stairs. He had a frankenbike with a 3 gear/inch low. Consider a triple bike with a 22 tooth front and a 34 tooth rear. If you still have trouble you can spring for a Schlumpf Mountain Drive and wind up with something like an 8" low. Harris Lake Cyclrey has them.

I regularly pull the road train consisting of the trail-a-bike with my 6 year old attached to my LHT, and the kiddicarrier with my 3 and 2 yr olds plus all their stuff for a day out attached to the trail-a-bike, (well over 100lb in tow) up a couple of miles of 4% - 6% incline with my 16 gear inch granny, easy. You can climb anything in you have low enough gearing, enough traction, and just enough forward motion to stay upright.

I suggest you get your trailer and do a small shopping load first, say 10lb at most, and see how you go.
Also, towing weights uphill is really good for you. It makes your legs bigger and stronger. This becomes very apparent when I ride with my weekend-warrior roadie friends on my 16lb Cannondale and have to wait for them at the top of every single hill.

I second cyclaholic post - if the hill is really steep you shift to granny gear and keep it moving.
You should be fine with your Trek, unless you changed the gearing.
I pulled 140lbs of kids up the 7% grade and while I was going only 4 mph we made it to the top.

I tow my boys in our Wike with my fixed gear Cross Check and while there are some hills that are steep enough I have to get off an push, for the rest I just mash up them. But my bike is geared 42x16 (71" gear inches) so it's a bit of a struggle. But anyways, it's do-able, and with gears much more so

Steve

My normal grocery load is about 45 lbs including groceries and trailer weight. Compared to the unloaded bike over the same route, the load costs me about 1 or 2 gears on hills. I pull about the same gear on the flats. And downhill...look out!

With the Xtracycle and similar load, it's about the same. I have to drop down 1 or 2 gears with the load. That's fine unless it's a hill that I already have to take in the lowest gear unloaded...

Eric

I pulled my utility trailer when I was running a 4 speed drive on my rigid mtb and have towed 80-100 pounds up some pretty long steep hills but also spend a fair deal of time climbing those hills on a fixed gear pushing a rather tall gear.

My new tow vehicle will be my RM Blizzard mountain bike as it has a 22:32 low gear and should allow me to spin my way up climbs with some significant loads and has the right brakes (disc / v combo) to provide adequate stopping power.

V brakes / cantis can provide adequate stopping power but if you take to towing a trailer regularly keep an eye on your brake pads to check for wear as this will be greatly accelerated as will the wear on the rims.

One another thing to note is the build on your rear wheel... you want the wheel to be properly tuned up and able to withstand the increased lateral stresses you experience when turning if you are towing larger loads. This is why I like having a 26 inch wheel bike for towing as the wheels are stiffer and stronger.

Thank you everyone for the great advice and experiences.
Looks like I'll take the plunge and buy the trailer.

Trailers are awesome things... I built mine for about $100.00 and love it.

Some important thing to consider when pulling heavy loads up hills are to gauge your strength/stamina, the conditions of the road, and the traffic. Where I live, there are many hills, and many people driving cars/pickups who don't give a hoot about a person on a bike with a trailer working their as* off to get to point "B". Don't feel bad about taking a breather after extraordinary exertion, even if it means pulling over midway on your journey.

I have an Instep Trailer. When hauling trash to the dump, or a harvested large deer or hog off the mountain, the best advice I can give you for uphill is to hit Granny Gear, and think of it as a way of life!

Schwinnhund <- best user name ever!!!

When I go for a big load of groceries, I go to a more distant store, but it is a store that is uphill all the way there, and so down hill all the way home (loaded).

Also, take along a collapsable cooler or similar to put milk and other stuff that needs to stay cool inside of. That way you don't have to rush home.

Great advice everyone thank you.

That's a nice trailer, man.