Don't be too scared FlyTier, you can do it. Stuff like facing bb/headtube are not always necessary, and if it is you can pay a shop not much to do it for you. I bought a Surly CrossCheck frame and built it up from scratch. I didn't get the bb/ht faced, I just installed stuff and it was fine. The only thing I relied on a shop for was to remove the headset from my donor bike. To press them in I used legendary framebuilder Dave Moulton's diy tools. Other than that my tools are standard (screwdrivers, wrenches) and the Nashbar "Essential" kit, bought on sale.

Knee pain: front or back? Rule of thumb is front = seat too low, back = seat too high. Don't give up on your bike just yet, 61cm for 6'2" sounds very reasonable to me. I'm a hair under 6' and I'm doing fine on a 60cm ChrossCheck.

Also, if your pain is in the IT Band (look it up), then you are probably like me with out-turned feet. When I force my feet to rotate inwards and be straight, I get IT Band pain. When I don't, my heels are hitting the cranks all the time. So I got pedal extenders to give me more room and I set my cleats to give me a foot angle which is natural for my feet, and now I'm great.