I installed my monitor just about where you are are thinking about. We have a refrigerator just outside the hall door so I went into the wall under it and up. There were existing wires in that area using the same space. The hall wall was 3/4 inch plywood so I needed to drill and cut for the monitor. Out bathroom is behind that area so I was able to run the wires up through a cabinet on the forward bathroom wall and through to the monitor.
The sea level tank monitor is a great system and always reads accurately. I did not buy the aladdin link, much easier to read it in the hall.