I would rather drive 5 hours from SLC to Jackson than 4 hours from Denver to somewhere else in CO. I think the drive would be easier and the skiing would be better when you got there. I like Grand Targhee and would ski there one day out of 5 if conditions were good and I wanted something different. JHMR is so much better than GT in nearly every way, that on a 3 day trip or even most 5 day trips I wouldn't bother with it. I usually enjoy a few days a season at The Ghee, mostly training days or lets do something different days. It's fun.
Look into the non peak times or packages for JH airport, check into the IF airport, or "Man Up" and pay the extra airfare for "The Big One". It's worth it!