I received the larger bottom bracket today and was able to install it using a hair dryer! (And a bottom bracket socket.) With the new, wider bottom bracket, it was easy to put on the new triple crankset adjust the front derailleur so it can shift for all three rings.
For those wondering, the hair dryer was for warming the frame around the bottom bracket. They first recommended a heat gun, but then pointed out that a hair dryer works as well. I also installed an adjustable stem. Pictures coming soon.
For those fellow Sofriders out there, I used Alivio M411 Hybrid Crankset (Black 170mm X 48/38/28) with BB-UN26 cartridge BB, JIS - 68x123mm bottom bracket.