Actually the 735 is every day. And it's probably not an extremely difficult upgrade either. I was on it last week and used miles to upgrade myself and a friend, but we could have easily made it with me doing an EUA and getting him a companion upgrade at the airport. F went out with one empty seat, and there were only about 40 passengers total on the flight (that's why all the other flights are ERJs). And despite the flight being less than 3 hours in length, ice cream sundaes were served after dinner. I'm assuming that's because it is an international flgiht, because I've never been on a dinner flight within the US of that length that had sundaes, and I've been on many that were longer (like EWR-IAH) where sundaes were not served.

Out of EWR, the current schedule shows 2-3 flights a day that are not ERJs.