I would suggest reading the TRW SWAP thread and the Wandering thread on the Monaco Owners portion of this forum, first. I know a TON of reading but worth it. I will gladly help you out but I have better luck explaining things to owners who have read the threads first.
Your Coach would benefit from a TRW SWAP, if it is available. Watts links are the next best thing to stabilize the H frame in an RR8 chassis. Your wander can be caused by a multitude of things but the TOP 2 are steering gear "free play" and UNWANTED H frame movement under the coach. BOTH fixable.
A TRW steering gear SWAP, parts only, about $850. Watts Links about $600 each. I do not know where you are located, I am in Georgia and Van is in NC. Mike Hughes is in Oregon (watts Links) Parts are heavy to ship.
PLEASE do some reading and then feel free to PM me on the forum or drop me an email at email@example.com anytime. I look forward to hearing from you.