I had a membership at the Pearl Ridge 24 Hour Fitness. Big, high ceiling, good/clean equipment (the big plastic coated weights in Kilo's 2.5, 5, 10, 15, 20, 25), professional visits (some local Hawaiian Pro Bodybuilders workout there and I saw Lee Priest and Cathy LeFrancois once)... it's the standard 24 Hour Fitness price table. From 17-39 USD per month... depending on if you want one gym location or all of them... or if you want 7 days per week or alternate days... also, prepaying a year saves a lot of money.
Man... that was about 2-3 years ago... but I think it was around $750 Ewa side... it was a 2 story apartment... I think 1 bedroom... it was nice. Get with the college and see if they have a roster started of people looking for flat mates...
The only problem I foresee is the Ewa side has a lot of Samoans (very large locals) with a lot traditional Hawaiian pride... if you are a white or black man you would stick out. I never had any problems with them... especially on Oahu (much more developed than the other islands) but some people I know have had run-ins... just so you know... but it's really not that big of an issue. Just get a good tan and pretend you are portugese... and say "brah" and "da kine" a lot

The thing they are kinda sore about is the fact that the islands have had a strong US presence there since WWII (several bases) and most of the pure Hawaiians are gone... many are now Hawaiian/Japanese (large Japanese presence there - almost
have to know Japanese and English to get a job anywhere near Waikiki)...
It's a very beautiful place to live...