I have a Gunnar Crosshairs that will be on touring duty this summer, pulling a Burley Nomad trailer thru Spain. Right now, I have a Shimano 600 series gruppo on the bike, with a 48-39 crankset up front and an 8-speed Shimano Hyperglide cassette in the back, all road parts. At first, on the advice of a friend, I was planning on simply swapping the
rear cassette for a MTB cassette, perhaps an LX or XT one, and getting a long cage rear derailleur. I talked to a guy at REI who has a lot of touring experience about this, and he seemed pretty sure that I should also change to a triple in the front. I don't have much money for parts--I'm saving for this trip!--but I don't want to be SOL while on tour in unfamiliar territory. So I'm considering buying piecemeal a whole new drivetrain, including new shifters/brakes.

I was wondering what would be a good set-up, piece by piece? I want to remain at 8 speed, I've heard it's a little more reliable and less maintenance than 9 speed, and I need to have a bottom pull front derailleur for the cross frame. So far, I've been thinking about something like: SRAM 5.0 11-32 cassette, Deore LX or XT rear derailleur, Shimano 105 52-42-30 crankset. I don't really know what bottom bracket/shifters/otheraccessories I need to get. So does anyone have any recommendations for an (relatively) inexpensive 8-speed drivetrain set-up that could take me happily through my trip?

I've never built a drivetrain before, so I'm sure there a number of smaller components in it that I've failed to list; what are all the parts I would need to replace moving from the current 600 set-up (including the brake/shifters) to a touring triple cranket?