Yes, you can just leave the OEM converter as is for when on shore power and make any deck mount converter into a portable battery charger to use off-grid.
Plug it into the gen when needed, use a cut off end of a set of jumper cables to put in the DC output terminals of the deck mount and clamp on to the battery bank. Put it all away when done recharging till next time.
You can still get use from a smaller solar set. It can't keep up, but it does extend the time before you need to get out the gen and do it that way. That might be enough delay to last you a long weekend without using the gen and you get home with the batts down but still above 50% so you recharge at home. Same effect as having an extra battery along but that won't fit in the RV, but the smaller solar set will.