Started a the simple project of installing a water filter under the sink in my 77 Argosy 26. I cut the copper and was going to use a compression fitting to tie it back together. looked like 1/2 inch. 1/2 inch fitting wouldn't fit so I went to 5/8. It was too large. Come to realize the water lines have been frozen in a former life but didn't break and that stretched the copper. Went back just forward of the bath and the same situation. Looks like I need to replumb. Can someone tell me how the plumbing runs behind the tub. I have tub on the left, toilet, sink, and closet on far right in this rear bath setup. Any suggestions for making this job easier? Thanks
--- Bruce