Hi guys, I'm trying to set my dad's 2008 Gary Fisher Mullet SS mountain bike up with some gears and could use some help pointing me in the right direction. The goal is to have just to put a rear derailleur with a single ring up front. My question is, can I just use the SS crank ( Bontrager Earl Singlespeed, 32T w/bashguard) and put a hanger/RD/new cassette on? If so, any suggestions as to a decent entry level (cheap) groupo? Thanks in advance!