I've been looking at converting one of my bikes into an ebike and would really appreciate some input.

I'm a fairly experienced short range bike commuter, I live and work in the city, haven't owned a car in 3 years, and am perfectly happy doing all my everyday errands and commuting on a conventional bike.

I find myself more frequently going to visit family that are about 20 miles from where I live, and am primarily looking for a way to speed up this trip, or make it more palatable when I need to bring a decent load with me.

I don't necessarily want to make the ride any easier, but where I average 20 mph for the ride right now, if I keep my effort even, I'd love to be able to average more like 25-30 mph. Also, when I have 30-50 lbs of stuff to take with me i can barely average 15mph, and generally loath the trip.

Ideally, I would like to convert the cheap cyclocross frame bike I have hooked up with a rack and panniers for this. This is my grocery/errands bike, and while I'm in the city, I don't think I'll have any real desire to have it run on battery power.

So, If I can average about 20 mph for an hour long trip, what type of power from the hub will it take to get me averaging around 30mph?

I would like to keep this bike fully functional without battery power, would a front hub only system work fine for a 150lb rider and 50 lbs of stuff (keeping in mind that I have no problem pedaling hard)?

Direct drive vs geared hubs. I like the sound of a geared system in that they have no rolling resistance when not providing power, but I've heard they are less useful at higher speeds and have a potentially shorter lifespan. How much of this is true, and how much resistance does a direct drive hub have when not assisting?

Any input is welcome, as are suggestions for specific kits that may fit what I''m looking for. Thanks.