I wouldn't be convinced the price is $4500 more. It might do you some good to let the Forester dealer know you're considering a similar RV for less money.
Depending on how badly they want to make the sale you may find they can lower the price enough so that the difference is less than $4500.
Especially if you're comparing MSRP to MSRP. If you're comparing sale price to sale price then there could be less wiggle room.
2015 Forest River Forester 3011 DS - 2007 Dodge Durango Toad