I haven't done that exact combo but I've been to both and often do combo trips like this (including a Wolf Creek and Telluride combo trip with similar distances, via Durango airport) I'm generally a big fan of these combo trips. Flights into Gunnison and out of Montrose can work but often adds expense to flights and rental cars so you might just want to fly in/out of Montrose . Montrose also has half as many cancellations (see:
https://www.pugski.com/threads/airports-to-avoid.16423/)
A three hour drive is pretty reasonable but be sure to factor in the cumulative driving impact and risk of delays due to weather. As I recall, there are not any major passes which reduces the risk of travel delay but of course snow can fall throughout the drive. It's unlikely but it's possible the 3 hour drive turns into 6 hours. Assuming average conditions, cumulative driving is likely 7 hours (Mon->cb 2, cb->T 3, T->montrose 1.5, plus .5 hour of weather delay) which isn't too bad assuming a 5+ day trip.
Full disclosure, I once did a Seattle->Apex->Big White->Silver Star->Sun Peaks->Seattle trip which included 15 cumulative hours of driving over 6 days and loved it, although I probably wouldn't squeeze so much into one trip again. I've done tons of 8 hours over 5 day trips (aspen/copper, panorama/banff, fernie/kimberley, killington/jay/loon, etc.) 7 hours sounds pretty reasonable.
Assuming your family is up for the driving, enjoy.