Welcome! Good plan not to wait for retirement! That will give you time to try it out while you're working and figure out what you do and don't want (while you have the cash to negotiate).
Montana in the summer means Glacier National Park, yes? or maybe just Yellowstone. If you do go to Glacier, and I used to work the West Entrance there, just make sure you find out if Going to the Sun road is open. So many people travel so far only to find out it is still closed sometimes even after the 4th of July depending on the depth of the snow and snow removal efforts (which they have to do by coordinates as they have no hope of finding the road without them, so thick is the snow in places). Certainly, you can see both sides of the park, but it is a three-hour drive around the park to get to the East Side or vice versa, and you still couldn't see much of the center of the park if Going to the Sun road is closed.
The web site will have the road's status as will Facebook. If you can, buy yourself an annual parks pass. Was $80 a few years ago. Glacier is $25 to enter (or was a few years ago, it won't be cheaper) and I believe Yellowstone is the same. The big parks take a lot of money to run, and get very little (or no) funding from taxes. By the time you dash through a few parks, Glacier, Yellowstone, Rocky Mountain, some things in Texas, you've spent $80 plus.
Unless you're disabled, then get a disabled access pass at any gate. Or if you're a senior citizen, 62 last I checked, $10 bucks for a lifetime senior pass.
Again, I'm so full of unsolicited advice tonight. It must be the chocolate I ate at 10:30 p.m.
Dawn