I've started doing a thing where I create point to point races that end at a fence or gate that have inaccessible areas behind them. Create the race, save it and run it. After the race, your car will be on the other side of the fence or gate and you are now free to explore the previously inaccessible area. For example:
1972 Reliant Supervan III in an inaccessible side street in Edinburgh.
1991 Bentley Turbo R at George Heriot's School in Edinburgh.
1991 Bentley Turbo R on Calton Hill with the Nelson Monument and National Monument of Scotland in the background.
That last picture was the closest I could get with the car (any closer and the car falls through the map). This is the closest I could get with just the camera.
1963 Volkwagen Type 2 De Luxe Forza Edition painted like the Rainbooms' tour bus at the Horizon Festival.
1963 Volkswagen Type 2 De Luxe Forza Edition painted like the Dazzling's tour bus at the Horizon Festival.
I plan on doing a lot more of these. The biggest problems are either there is no ground and the car just drops through the map, or the map goes almost entirely black and you can't see where you are. The good news is you can go into photomode and you can see again. Be careful with the photomode camera, though. If you move the camera from the inaccessible part of the map back to the game area, you can't go back in. You have to exit photomode and start over.