@KATENESS To open an existing resort in IP, you have to be in build or buy mode. You can either do it in Edit Town, or just enable testing cheats and shift click on the lot and choose "build (or buy) on this lot." Then ctrl+shift+click on the resort desk and choose Resort Management. You then have all the same options as you have in live mode with a resort your sim owns.
@SPARKY1922 Yeah, it didn't cost my sim anything to take over Hobart's, and just removing all the brambles and buckhorn gave her money to make a few improvements. By then she had also finally opened that level 10 treasure chest in Pearl's Deep, so she had enough money of her own to buy one blueprint room, so I got the party room with the food stand and firewalk pit. She made $342 on the first morning and then sold the large plutonium ingot and large cut rainbow gem she got in the treasure chest at the consignment shop for over $20,000, so I did a few more upgrades, including upgrading the tower, and the next morning she got $542. So it's paying for itself, and when she moves away from IP, she'll get a good chunk of money from selling it. So it was a good financial move.