atom
    //vars to hold the directions
    var/list/enterdeny = new()
    var/list/exitdeny = new()
    var/list/enterallow = new()
    var/list/exitallow = new()
    //Params vars to covert the lists into 
    var/enterparams
    var/exitparams
    var/enteraparams
    var/exitaparams

turf
    icon = 'icons.dmi'
    cave
        icon_state = "cave"
        layer = MOB_LAYER+1
        enterdeny = list(EAST,WEST)

Then next comes the proc that adds sets up the lists manually so the user doesn't have to but I won't put that on here. But here's where I think the problem is.
<dm>    Enter()
        if(Rl_enter(usr))
            enterparams = list2params(enterdeny)
            enteraparams = list2params(enterallow)
            return 0
        else
            enterparams = list2params(enterdeny)
            enteraparams = list2params(enterallow)
            return ..()

    Exit()
        if(Rl_exit(usr))
            exitparams = list2params(exitdeny)
            exitaparams = list2params(exitallow)
            del(enterdeny)
            del(enterallow)
            return 0
        else
            exitparams = list2params(exitdeny)
            exitaparams = list2params(exitallow)
            del(exitdeny)
            del(exitallow)
            return ..()

atom/proc/Rl_convert() //This takes care of turning the lists inot params at runtime
    enterparams = list2params(enterdeny)
    exitparams = list2params(exitdeny)
    enteraparams = list2params(enterallow)
    exitaparams = list2params(exitallow)
    del(enterdeny)
    del(exitdeny)
    del(enterallow)
    del(exitallow)

atom/proc/Rl_enter(mob/M) //This and Rl_exit() control the allowance of movement
    enterdeny = params2list(enterparams)
    enterallow = params2list(enteraparams)
    var/direc = get_dir(src,M)
    if(direc in enterdeny)
        if(direc in enterallow)
            return 0
        else return 1
    else return 0

atom/proc/Rl_exit(mob/M)
    exitdeny = params2list(exitparams)
    exitallow = params2list(exitaparams)
    var/direc = M.dir
    if(direc in exitdeny)
        if(direc in exitallow)
            return 0
        else return 1
    else return 0