I had same problem with my Jayco. I found the name of the shower door manufacturer on the door. I called them and they were able to get me new rollers. I did see some rollers at RV store after repair was made.
Take the unit and a car to an RV park or campground close to your home. Live in it for a few days (cook, use bathroom, dump, fill water, wash dishes, check the frig, furnace and AC. If there is a problem or forgot something you're near home.
Settle in for a few days - enjoy and learn.
Welcome to RVing
We've done it both ways - solo and with a group.
The first trip to AK was with a caravan - www.alaskarvtours.com - we met some great people from across the US and have been getting together every year since 2004.
The second and third trips were on our own, having been with Spike on the initial trip gave us the confidence we needed.
But either way go and enjoy.