Double check the status of the border crossing on 93 before you go, and be prepared for long wait times. (We were thinking of going up that way in Sept. of last year and there was a closure.) And you probably already know, but if you do have to cross the border on the east side for some reason, you will have to drive around the southern edge of the park to get to West Glacier, as there are no large RVs allowed across the Going to the Sun Road. And as others have mentioned, the GTTSR may or may not be fully open at the beginning of July.
Have a wonderful trip! Hope to get to Jasper and Banff ourselves someday.
2019 E-Pro 14fk