You can look online and get an idea of what they'll say when you call in the morning.
If the GCH is a challenge for the budget don't be afraid to stay on Harbor.
Scooter rentals in the area have free delivery/pick-up of their scooters.
The scooter will be nice going to and from the parks whether you're on-site or off.
Here's a map that you can check distances using the pointer. If you do stay on Harbor it will give you an idea of where places are located.
http://wikimapia.org/#lang=en&lat=3...&m=h&gz=0;-1179189741;338091968;0;0;37549;665
This link will give you an idea of various places in the DLR area. Keep in mind IT'S an old thread
http://www.disboards.com/threads/walking-distance-hotel-list-w-discussion-details-of-hotels.2796786/
We usually take a taxi to/from the airport. Having a car isn't necessary for us once we are there.
The only time we have had a rental car is if we plan to side trip from DLR.
Good luck in your planning. The first week of March is too far away.
Geemo