In Sunset Valley, I change the two beach lots without a lot type to Beach prior to playing.
When I get enough money to do so, I purchase one of the beach lots (normally the one behind the Wolff house), go into build mode, go to community objects, locate the wagon, and place it, usually along with fairy arboretum and Vault of Antiquity. then I return to my game, which sells the lot, and I play on.
I've never had any problems doing that, and can interact fully with the wagon, arboretum and vault afterwards.