Believe it or not, I forgot to put antifreeze in the traps of my kitchen sink, lavetory and shower. If anyone has a link to an RV parts store than can tell me which traps I have in my 2001 Jayco Designer 27RKS I would appreciate it. The camper is 300 miles away and I would like to order new ones before I go because I'm guessing they froze and split.
There is a good change you will be ok. Since there is plenty of expansion room in a trap as opposed to a water line, it is less likely you will have an issue. If I remember right, all my traps are cemented in so it may not be as simple as just unscrewing them like a home faucet.
I had a buddy that left water in his entire system for 6 years and the only problem he had was a seal inside his kitchen faucet - I was simply amazed.
I would guess that you will be ok. By the time the cold weather set in most of that water should have evaporated. Also as already mentioned there is room for expansion.
__________________
2011 Eagle 330RLTS with just about every option.
2017 Silverado 1500 4x4 5.3 with tow package. (no, we don't tow the Jayco with it.)
2018 Surveyor 265RLDS well equipped.
Life in the slow lane is still life.