The difficulty with a re-fi cash out for you is the age of the mobile home. The HUD guidelines have a cut off of 1976 for mobile homes. That leaves you with alternative financing like a hard money loan and that is going to cost you more than the extra funds may be worth to you. Hopefully a BiggerPockets member who is a lender can give you some better alternatives. In fact I would love to hear them because I have missed out on some really great rental opportunities because decent financing isn't available for homes older than 1976. Google "what is the cutoff age for mobile home financing" and you'll get a better explanation as to why it's so difficult.
Anyway, your head is in the right place. Keep studying any BP data you can find here on the site. Continue to ask questions on the forum. I am hoping someone gives you better news than me. Worst case scenario you come up with a 3rd Option that lands you a home run deal.