First Time Winterizing an RV

I always have done both, blow out, then antifreeze in all water lines. I have used 35-40 p.s.i. as that echo's the recommended water pressure. Probably doesn't matter since I use anti freeze anyway. Last year I had the dealer do it, while I was getting other work done. I kinda liked not having to do it and might continue having it done. Costs about 125.00 bucks, and I have them do a quick inspection. 

Others got back to before I did on #1, but on #2, open the low point drain without any air pressure. You want to open them, then blow out the water.

+1 to Dirt Sifter.

On mine, the drains are in the center for the black and gray water tanks. Tilting the trailer won't help. OTOH, the fresh water tank has a drain that is closer to the driver's side so tilting would likely help there.

It’s just 1/2 inch PEX. So you can use any PEX to male NPT adapter and then a female NPT cap. For example:

https://www.lowes.com/pd/Ecopoly-5-Pack-1-2-in-Plastic-PEX-Barb-x-1-2-in-Male-Pipe-Thread-Adapter/1002635292?cm_mmc=shp-_-c-_-prd-_-plb-_-google-_-pla-_-142-_-sospipeandfittings-_-1002635292-_-0&placeholder=null&gclid=Cj0KCQiAwf39BRCCARIsALXWETxVAN42tvQjFHDcnNIQbb9fbn4uv4O6ljwXw6OPpsEJJ4WSeAmjl6IaArlbEALw_wcB&gclsrc=aw.ds

And

https://www.lowes.com/pd/LASCO-1-2-in-x-1-2-in-dia-Cap-PVC-Fitting/3371572?cm_mmc=shp-_-c-_-prd-_-plb-_-google-_-lia-_-142-_-pressurepipeandfittings-_-3371572-_-0&placeholder=null&gclid=Cj0KCQiAwf39BRCCARIsALXWETyAArKzsuW8xUYtNBHEzDGFPJlrXZ2gvdFnv0jIwSb6xoWP70jOPzcaAuPcEALw_wcB&gclsrc=aw.ds

You will need a PEX crimp and crimping tool for the adapter if you don’t have one. Or you could get a PEX push to MNPT adapter and cap that.

https://www.lowes.com/pd/SharkBite-1-2-in-Push-to-Connect-x-1-2-in-MNPT-dia-Male-Adapter-Push-Fitting/1000182549?cm_mmc=shp-_-c-_-prd-_-plb-_-google-_-lia-_-142-_-potablepipefittings-_-1000182549-_-0&store_code=447&placeholder=null&gclid=Cj0KCQiAwf39BRCCARIsALXWETw8CJ3rSR-3YIpRGkt97Mfoku7Nx5sJujlWs5tZQf4wsQgbhbqiE2caAorWEALw_wcB&gclsrc=aw.ds