is it permissable to use fenced in pathway to go to ohel of labavitch rebbi
I cannot say definitively if you can or can’t go, as I have never seen it. However in general; if there is a fence that is 35 inches high (10 tefachim) that separates the any graves from the pathway, and there are no trees that hang over any part of a grave and the pathway, then it should be alright.
Also a Kohen may surely not enter the Ohel.
As a general rule it is advisable for kohanim to stick away from cemeteries, because for them it is fraught with the danger of mistakenly becoming ta