I paid $2,900 for a 20x40, 11' legs which gives me about 14 feet in the center. I park the TT towards the left side and have enough room to park the Ram alongside and even extend the awning. I don't have slideouts but if you park your unit toward the center 20 feet will probably allow extending the slideouts and awning.
At some point during every day you suddenly realize nothing else productive is going to happen the rest of that day. For me, it usually occurs around 9 am.
Vengeance 25V (the Harley needed a home)