Well respected consumer report magazine says "73% of extended warranties are never used".
You get out on the road and have a failure then good luck finding someone to repair. $4500 is a huge amount, bank that and self -insure,you will be way ahead. Find a local mechanic or mobile RV repairman to do things that may be needed. There are some of the "what if's" out there that feel the need to insure against just about anything, makes me chuckle.
Follow recommended maintenance procedures using quality products, especially engine oil. I use Mobil 1 from Costco and Wix or NAPA filters. Motorcraft also. Use a fuel stabilizer in your gas tank, especially if it is going to be stored and run your generator when the additive is in your tank.
For me, the extended warranty program is one big money maker and borders a scam. As stated read and understand WHAT they will pay and what they Won't pay before you purchase.
If the impression is that every squeak and rattle will be repaired and every broken door latch etc, sorry.
Today's engines are not your father's engines. My vehicles have all gone over 200K without major issues, my step-son's just turned 300K on his pick-up.