Needles Ca. / Topock Az. on the north side of the sandbar. Topock is closer by about 13 miles (wild guess)
Havasu Landing Ca. / Windsor Az. in Havasu, on the south side.
H.L. is the indian casino on the N/W side of the lake from the Island.
If I were you I would go to Havasu to stay so you could Really have more variety than just the sandbar.