Very confusing water issue - not flowing to some faucets after de-winterizing

[Airmon]

Hi all, 

We're in a 2003 Southwind 32' Class A. We have spent most of decade on the road as full timers ( the last couple of years sharing that with a diesel trawler doing the great loop ) so we're not noobs, but for a variety of reasons we've been stationary in Virginia for the last year or so. 

While we're in southern VA and it's not as cold as some parts of the states, winter temperatures below freezing are enough of an issue that we winterized the RV for the first time late last year. 
The one previous time it was winterized was when we bought it about eight years ago and that was done with the pink non-toxic antifreeze. It took us FOREVER and several tanks ( 100 gallons ) of water run through everything to get the taste of that antifreeze out of the system. I have to use that on our boat when we winterize and I rather hate that stuff. I'm not even sure the well here at the house has enough capacity to run a few hundred gallons. 

So this year I got a hookup to use my air compressor to blow the water out of the lines.
I drained all the liquid from all tanks and the water heater, and as much water as I could get from the low point drains.  I then hooked  the air line up to the city water inlet.  With the compressor regulator set at about 30 PSI I proceeded to blow out all the lines until I got air out of all water outlets. Then pink antifreeze into all the traps and a gallon or so into the black and gray tanks.  Everything seemed fine and the RV sat in the yard until I went to get her ready for a short trip this spring. 

I added water to the tank, flipped the pump on and purged the air from the water heater, low point drains and the outside rinse faucet. So far, so good. 

Then, I went inside to start purging the lines to the sinks ( bathroom and kitchen ), toilet and shower. 
The shower worked normally, but the other three...didn't. The kitchen sink and the toilet have basically zero water coming out of them ( the kitchen faucet gurgles a bit sometimes when the valve is open ) and the bathroom sink flows a bit, maybe 30% or something, but not always, just sometimes. It's the same for the hot and cold water in both faucets, despite having pressure in the water heater tank. 

Ambient temps were in the 60's, so there's no water frozen somewhere. There's no break, because there's no water leaking and the pump isn't cycling unless I open one of the other, working, water outlets. 

Just no water coming out of the faucets and the toilet. Could there be check valves somewhere that are stuck? Any idea where I'd look? Some of the lines are absolutely inaccessible under the floor and there's no way to replace or get to them. 

I'm open to suggestions on where to look or how to diagnose this, because I got nuthin'. 

Thanks!

[Airmon]

The faucets themselves are fine. There's no pressure/flow in the lines to the faucets. 

[MNtundraRet]

"The fact that the bathroom faucet has started working is making me think it's an issue with a check valve or something similar somewhere, like to keep water from flowing back out of the water heater into the cold water lines. 
I guess I need to start thinking about tearing the floor out."

I would suggest bypassing the water heater to see if you get water that way.

[Airmon]

AFAIK, there is no water heater bypass. I can tell you for a fact that the water heater is getting pressure and flow. Opening the pressure release gets a gush of water. 

[craig7h]

Have you checked the screen on the water pump. Sometimes the screen gets clogged thus causing a problem. Also have you checked the screens on the faucets, they also could have become clogged. The toilet on the other hand I have no idea. You might also want to check your winterizing / dewinterizing values related to the water heater. They may not be in the correct position which could cause this kind of issure. 

[Airmon]

I have not checked the pump screen, but that's not the issue. If it was, water flow would be reduced more or less equally at all water outlets. Instead, water flows fine and strong from the shower, low point drains, outside rinse and ( sometime within the last two weeks since this started  ) the bathroom sink. 

There's still zero flow at the kitchen sink and the toilet. 

The fact that the bathroom faucet has started working is making me think it's an issue with a check valve or something similar somewhere, like to keep water from flowing back out of the water heater into the cold water lines. 
I guess I need to start thinking about tearing the floor out.