I agree, if you are still under 250 hours, there will be a lot of changes in the industry before you're eligible for an ATP.

SLC is OO's most senior base easily. If I had to predict anything 3 years out, it's that SLC will still be very senior. Pretty sure we're the only show in town there, and lots of folks here want to be there. Some new FOs volunteer to be ground school instructors on the CRJ to get there fast, so that's a possibility for you. You give up most of your flying/career progression though.

BOI isn't too long of a wait on the ERJ side right now, but it's anyone's guess what that'll be like in 2+ years. You'll have to wait and see.

I'm not sure how senior SLC is for Delta, but if I were you, I'd reconcile myself to commuting for 10+ years if you want to live in SLC and move past FO at SkyWest. FO pay right now is mid 30s. As someone else said, if you are willing to give up a lot of your days off and try to work the system, you can make a bit more. Of course, in 2 years, pay throughout the regional industry is likely to be very different than it is today.