Welcome to RVF,
@CMRobbins; glad to have you join us here. And, sorry you are having freeze-up issues. Since you have gotten the heating system back into operation and some water is flowing in the bathroom, I think the frozen pipe section should thaw within a few hours...IF...the frozen section is in a heated area. If not, you will need to apply some heat. No open flames or anything like that. A hair dryer judiciously used to prevent overheating the PEX, or placing a 40W incandescent bulb (like a trouble light) in the area of the frozen pipe (if you can locate it) will be sufficient. Take your time; don’t overheat anything. Once water can start flowing past an ice blockage, it will melt quickly. Periodically try your faucets in other areas of the RV and if even a little water flows, let them run a bit to speed up the melting. Be sure to monitor all faucets left open to prevent flooding anything.
One thing I would be concerned with would be the integrity of the water system after it has frozen. Most newer coaches use PEX piping and it is fairly tolerant when it freezes, but the expansion of the ice can push fittings apart and result in a leak. Be sure you monitor your storage compartments and the underside of your 5th wheel for signs of water leakage. I think you should be fine, but don’t take any chances; check all areas where plumbing runs.
Good luck.
TJ