Thats where we are at also.........2 adults, 13,11 and a 5 year old. You can forget about RPH.......unless you want to pay big $$$ for a suite. We were VERY cramped at RPH........they gave us a rollaway bed and the only place it would fit was in the sink area by the door! Still a GREAT resort, we LOVE it,but I wish they had deluxe rooms. We are prob. going to split stay at HRH,PBH in the double queen deluxe room. It has a sofa bed and two queens. They also have "kid suites", but they are a lot of $$$, but they look nice and comfortable! If you dont mind spending some extra $$$........I would go for the "kid suite". They have ALL the room layouts on the hotel/resort pages on the Universal Orlando web site.
BTW........I am not 100% sure but your 18yo, may be considered an adult. I think loews has a policy of only 2 adults per room ??? You may NEED two rooms or fudge a bit on the oldests age. Like I said,I am not 100% sure though. 17 is considered a "child" I think.
Good luck.
Later..........Syndrome