I've been through this. The most difficult thing about switching the roadster is it's complex relay system for channel switching. Well it's not really that complex however the way to get it switching right can be. There are external jacks on the back of the amp that will allow you to switch everything but tuner/mute. Conceivably you can create a foot switch yourself and turn on and off channels and the other functions with those jacks. Your mileage may vary. As stated above, the channel switching matrix is complicated as you need whatever you build to "shut off" channels that aren't in use. The other functions, solo, reverb and FX loop can be actuated with a simple latching foot switches.
If you have no other requirements than to switch the amp, get a roadster foot switch and be done with it. If you have midi enabled gear that you want to switch as well, your options open up a bit.
Several manufacturers make midi enabled switching systems. Most popular seem to be RJM Music Corp's Amp Gizmo, and Voodoo Labs GCX. Both of these systems will require a midi foot switch to control them. They are significantly more expensive than the roadster foot switch but offer a lot of options if you have a bunch of midi rack gear.
There are other manufacturers but for most people's needs RJM and Voodoo Labs are in the right price point. There are a few others on this forum that have implemented these systems.