Here's Glacier's web site and note that all national parks, national monuments have a wonderful site like this. It gives details on things to do, camping, road information, etc.
https://www.nps.gov/glac/planyourvisit/gtsrinfo.htmIf you were planning to take your RV on Going-To-The-Sun Road there are size restrictions. There's also a free shuttle that takes you to the top and also vehicle tours. The road can close at any time due to weather but officially it'll be open until Oct 16. You shouldn't have any problem with your timeframe.