I recommend Kemayo's
QuestPointer in conjunction with the aforementioned TomTom - and then just utilising the built-in map and blue areas for tracked quests as much as possible.
QuestPointer is a fairly basic but very helpful add-on that just points you to the nearest tracked quest (it does *not* tell you what the "best" thing is for you to do or where quest givers are - but that's where Wholly/Grail circumstantially fills the gap if you need it).
I also recommend some add-on to automatically track your quests.
I prefer
SorhaQuestLog for this, having used it for a long time, but it's practically a full replacement for the built-in tracker and also the list side of the quest log, so it may not be to everyone's liking.
(There's no need for any paid services or alike.)