To help with your steering issue you're going to need a Roadmaster Reflex Steering Stabilizer. One of two parts is going to fit your 2005 Beaver Monterey depending on the suspension you have. If you have an airbag suspension or if your motorhome is a Monaco chassis you will need # RM-RBK6-RSSA. If you have leaf springs, then you will need # RM-RBK8-RSSA.
I have included review videos on both for you to take a look at. view full answer...
The Draw Tite part # 75673 that you referenced is a confirmed fit for your 2018 Subaru Outback Wagon and would be a great choice.
For trailer wiring you'd then want the # 118467. view full answer...