Rigging Bachmann k4 for DCC?

[270weatherby]

I have a DCC ready K4 4-6-2. I'm wondering if anyone has installed decoders in DCC ready locos before, how much of a hassle is this to do? Also I was hoping you guys could suggest a DCC controller. I'm looking at the MRC Advance Express. I would like to run 2 possibly 3 loco's (3 would be rare if ever. More for after expansion down the road). Would the Express do the job? Here is a pic of the track plan.

Thanks