Since you live in CO and will be using it at higher elevations, far and away your best choice will be EFI. Don't mess around and do it half way. Use one tank with an in-tank pump. Don't waste your time and money on accumualtors, muti tank switches, two pumps and all that other complicated junk. It just doesn't work at this altitude with the oxiginated fuel that we are forced to use. Talk to those of us here that have had EFI for a while on daily driven rigs.I tried all that stuff when I first converted to EFI, in an effort to save some money, but it basically caused me to spend more to get it right. I have all that junk still, if you really want to try it. You could probably use your stock rear tank and tee into the vent line for a return, if you use a really good HP in-pump mounted close to the tank. But again, do it right the first time so you don't have to do it again. I now run 2 tanks, but I use the dash tank switch to trigger a relay for a cheap electric pump to transfer from the front to the rear.
As far as your Edelbrock carb, I ran a Carter AFB, before I went EFI about 4 years ago. It worked best offroad when I did the following things to it, 1/2" phenolic spacer to isolate it from the direct manifold heat, off-road needle and seat, float level just a hair below spec, proper jetting, and a fuel pressure regulator. I used to turn my fuel pressure regulator down from 6 to 1 1/2 to 2 when I turned in my hubs. It then ran about as good offroad as the stock 2 bl..
There's nothing like that horrible feeling when you are in a precarious situation and the carb starts acting up or the engine dies. Spring Creek Trail gave me religion about having EFI a while back.
