Here's my concept for a Rivertown expansion. It isn't as pretty as any of my other maps, but it gets the point across well enough. There is:
a new indoor VIP Lounge
like at Kings Dominion
a new lake
much smaller than Swan Lake, but more water in Rivertown nonetheless
hopefully the new trees and foliage could grow in nice and tall
any new trees would also be placed far enough away from Diamondback's helix
the water finally returned under The Beast's pre-lift section
this would presumably come alongside a Gravity Group rebuild of the pre-lift
the ride exit and Fast Lane lines would be relocated/reworked to be separated
a new Refresh Station, bar, or gift shop in the former Beast Canyon Cold Drinks area
housed in an addition/new construction to the right of the queue entrance
this is where the exit would empty into, with the Fast Lane line entering nearby
a new outdoor amphitheater
spiritual successor to the Rivertown Reel and the Back Porch Stage
perfect for smaller shows
a new family-friendly flat ride
I have no opinions on what it could be, but the ride pad is a similar size to Shake, Rattle & Roll
All of this would replace the Tomb Raider building and provide new things to do in this recreation of early Cincinnati that celebrates its roots as a river town. I think the outdoor amphitheater could instead be an indoor venue like the Red Garter Saloon — though I hesitate to use the word "saloon" because of its Frontier/Western theme area connotations. The last new building on this expansion map could be anything, although I wouldn't be opposed to having it be a new quick-service restaurant. The service road that is behind TR:TR's building would be relocated further behind the new construction.
The removal of the Tomb Raider building would likely mean that we also lose the foliage growing on top of it, but I think it might be worth it for this kind of expansion. The size of the new lake is another pain point for this idea. I would love to see something closer to the size and feel of the original Swan Lake return, but I think this is more realistic in the short term. One thing I'd like to see that isn't in this map is some theming or foliage near the railroad tracks. The area as it stands is very barren and lifeless. This might even offer up a new opportunity to reuse some of the old nature trail path for a new Trail Haunt.