I would suggest looking into Marriott resort type properties, or at least a room with a fridge and small kitchen (so you don't have to eat out all the time). If you like nature, I would recommend going somewhere that you can explore the national park system -- relatively cheap -- by day, then return to your Marriott resort hotel by day.
"Nature" means different things to different people. To me, there is beautiful nature in urban settings with great park systems and waterfronts (ie Boston, Portland, OR; Seattle). I might suggest an urban destination so you can ditch the car and go by foot and public transport.
I'm not much of a travel expert, but I do know that the best ways my husband and I have found to save is to ditch the car/rental car (rely on public transport) and to find a housing arrangement with a kitchen so we don't have to eat out all the time.