What can I use this sim for?

Don't offer money! You'll have every noob in SL applying to do it. Ask if there is someone who would like to do it first, get credentials, then ask for a quote. I would edit your post.

Re the art thing, have a look at Brooklyn Is Watching, this sim lets people place art there for one week, look at some of the work, whatever you like you could ask the artist if they wanted to display a piece of art on the sim for a limited period of time, artists are poor avatars on the whole and most would be happy to show their work. You could have a central plinth somewhere for the art to go, you could allow the artist to show more than one piece or have 4 artists showing their work. You would control this by having a prim limit per artist or piece of art.

Maybe you should take advantage of the river.
When my land in Whiskey extended to the riverbank, I toyed with the idea of running automated river trips up to my roadside/riverside parcel in Tethys. A problem there was that the move from my land into the river involved immediately crossing a sim boundary and dropping down a steep Linden cliff to the water beside the dam.
Your sim alows for a dock build on the river.

The dam makes it difficult to do normal boating Eastwards, but following the river Westwards is a really great trip, with narrow gorges and rapids.
There's a Linden installation at the Eastern edge of Tethys where people can take inner tubes and raft down past the rapids and a waterfall to get back down to your sims.

The high mountain area in Tethys is an interesting example of someone being generous with their space. Between the Johan Pintens, Babenco Brothers and The Governor and a few others, this is quite a play area. Maybe the policies there are a bit too trusting for your location, but it's worth a look for thinking outside of the box.

I'd go for spectacular builds in your place, with links to the nearby spectaculars, but that's easy for me to say

I know someone -- I'll see if they're interested.

Goodwrench Grayson is the one with the actual Mushroom Kingdom build. It used to be on a hill in the Davenport region, where Stephenscairn Bluff is now. He would be the one who would have it in his inventory. I just owned the land it was on for awhile.