Personally I wouldn't do it without EP. We stayed onsite for one night, so both days in the park were had the unlimited EP. We loved the ability to just walk on the rides (or have a very short wait), and were able to go at a relaxing pace. We loved it and plan on doing the same thing when we go back next year.
If you break its down its roughly $250 plus tax for a night at RPR. A 2 day pass is $130, or $260 for 2 people. So, just over $500. You would need a hotel for a night anyway which would be at least $100, so thats $400 for 2 people to go to the parks for 2 days with unlimited EP. $100/person/day...not too bad!