I doubt A10 would take RMU, but if I was in the admin I would at least try like hell to get invite. If they don't, then fine.
When the Patriot league was mentioned, at first I laughed to myself. Many of those schools and their fans have a very high view of their academics, and in a majority of the schools I supposed they are right. RMU's academic profile is improving greatly, but would the PL members think it is high enough to join their club? That would be the only reason I can think to keep RMU out. They would be a bit of an outlier, but travel would be easier than NEC I think for RMU. I think it would be great for RMU to be admitted to the PL, and would cover a lot the sports, maybe all of them other than hockey but they seem to have great current homes for hockey. Although I agree with ORMC that bball and probably hockey are now the premier sports at RMU, I am football first, and the PL would be great for football, really really great in my opinion.
All of the above rambling, led me to vote for the PL. Best possible overall fit for the school, though I think academics might keep them out.