I have to second getting EP's. BUT, if you are going during a "slow" time, then I don't think they are needed.
Our first trip to Universal side only, we bought tickets and EP's, one ride only on each. The only attractions that had long lines, at that time, were Minions and Shrek. It was a while ago, LOL. We really didn't need them for any other attractions.
Now, we stay at RPR and get unlimited EP"s. The resort is great and a big part of our stays. The boat ride to the parks is beautiful and relaxing. You go through security at the boatdock, and that's it.
The main thing I like about EP's is that you can do what you want, when you want, and multiple times in a row if you want. No fp times and limits. It really is a great system. I wouldn't go without EP"s now. We are going to buy AP's next trip too.
You can buy EP's in the park at any time, too,, but they have a limited supply of EP's, so it's a gamble. We have never bought them in the park, but you can.