If it's in spring fruita is fun, but the FFTF makes the trails busy with "others" and MTB trail traffic is unfavorable IMHO. CB is epic riding but you'll wannna wait till at least june to get to the greatest trails that you'll ever ride. They are in CB. Epic singletrack in heartpoundingly senic mountains. If you only get to choose one CB has way better trails, and mountain life.
You can ride to silnlgtrack from town in CB and you'll drive and park in Frutia.
CB is a resort town with all levels of accomidations from cheap hostles to luxury homes, Frutia is mostly interstate hotels or camping.
CB is pure rocky mt singletrack, frutia is red desert trail.
If you come for the FFTF it's in april and not many other trails in the state are open, the CBFTF is in june? and you could possibally hit the Monarch crest trail or other great CO trails on the drive, in april we'll still be snowed in up in the mountains, limiting other riding.