Also, in a studio you would get a kitchenette with a small fridge, micro, toaster, coffee maker & "kitchen sink". This could defray the cost of light meals like breakfast or even lunches if you are going to be at the pool anyway.
The bus service from OKW is great to all the parks.

You can also get a boat from OKW to DTD where Pleasure Island is. You would most likely have to return to OKW by the bus if you did do Pleasure Island late into the evening as I think the boat only runs until about 9:30 or 10:00.
As far as renting points & how many you would need - you need to know the dates you'll be there. I don't have my point book right in front of me, but I believe as another poster said - the BWV are about the same point value as OKW & the Boardwalk is an AWESOME place to stay!!
Head on over to the Rent/Trade Board in this forum & ask A LOT of questions!

If you do end up renting, before sending any money make sure you ask for & check references. We had a great experience renting points from someone on the boards before we bought & became owners at OKW, but we checked references & also made sure that the person we rented from had a lot of posts.
Oh - just a tip on food. Someone mentioned splitting meals. At the counter service restaurants you can also order a sandwich without the fries & it is a little less expensive. One order of fries from one meal is probably enough for 2 girls to share. You can also just get ice water in a cup if you ask at the counter service restaurants, you don't always have to get the bottled water for $2.50. Sometimes I want a soda, but other times it just won't quench my thirst & I really want water, but don't want to shell out $2.50 when I know it will just get warm because I won't finish the whole thing right away.
Head on over the Budget & Tip Boards for a lot of other money saving tips & some additional tips in general. The information you'll get will be very helpful.