If you are not staying their can you still pay at the desk to use the pool and hot tub?

Only if you are with someone who is a registered guest there.

Since 2014, we do not accept persons from outside the park to use our facilities unless they are visiting/staying with a registered guest already staying for a reservation in the park. - Trailer Inns RV Park Management Team

We only stayed 2 nights, I can't tell.

I'm not sure. I would call and ask MNGMNT. Victoria or Bill