The 4G 130-amp alternator will survive quite nicely at idle. It has dual internal fans. Believe it or not the issue here is the battery itself and it's charge acceptance ability. You can kill about 5 birds with one stone. Replace the battery. If a larger battery will fit choose a group 29, 30, 31 which are all the same size. But AGM. Absorbed glass mat.
Without touching anything else you start the engine and presto you almost double the amperage going into the battery from the engine alternator. Next, is the point you can SAFELY Discharge an AGM to 20% of capacity 80% discharged a few dozen times in it's lifetime without impacting it's superior lifespan.
When budget affords it then go for a larger converter but for now it would be danged tough to get what a larger AGM battery offers. It's a fast and easy fix and you compromise nothing after the show is history and you continue RV'ing.
