I've only driven through.Not sure it's even developed to the degree you're hoping for re: kid activities (zip lines, tubing, etc.) Just the traditional (presumably winter) activities. It is a very small town.
Not too many airports around. Nearest major one of course is Calgary/YYC and it could be challenging in winter to get there (road isn't particularly treacherous but it's still winter). Smaller, nearer airport would be Cranbrook (with commensurate small plane service). I didn't even know Fairmont had an airport or air service. Don;t even think about Castlegar as it is further away, requires travelling on the Salmo-Creston highway and is often socked in.