There is no reason to go to an RV dealer for your WDH. Any trailer sales lot, will get what you need probably much cheaper than an RV dealer.
People on this forum are real fond of spending other folks money. You do not need to break the bank for your system. I got a "cheap" pro pride system for 279.00 dollars. It function just fine. Just make sure that the bars are right for your weight. Base all your decisions on the gross weight of your trailer. If it hasn't bee molested there with be at least one sticker on your TT showing the GVW.
If you are like most of us you need to balance cost against usage. Two or three short trips a season does not require the same outlay as a cross country trekker.
Do some googling some reading and forge on!