Maurice Jondrelle is an idiot who's going to get us both killed

I found that going off road was helpful as it avoided most trolls and bandits. With that said, he only just got to that tree alive.

At one point while I was escorting him he had an axe in his hand... I have no idea where he got it from because he usually just punched everything else. I've finished that quest now and didn't try this, but you may be able to trade some weapons with the fool like with other companions. Worth a try.

In the end I needed to use the console to offset his suicidal lack of tactics and keep him alive. I clicked on him with the console open (to make his actor number the active one) and typed:

  setav health 100

This seemed to keep him in decent health for the rest of the trip, including a dragon attack. By the Nine Divines, he tried to box with a dragon...

To get Maurice to Eldergrove alive, the biggest challenge was the bandit towers. I did not know to clear them out in advance, because I had no idea what a huge liability Maurice is. (Do you know he even gets nasty when you use Healing Hands on him?) So what I did was sneak as close to the bandit towers as I could get, then sprinted. I headed for the nearest landmark past the towers that I could discover, which was not too far at all. Then as soon as it showed as a discovery, I used fast travel: once away and once back, to make sure Maurice and Lydia showed up by my side on the far side of the bandits.

There was also a pair of dragons haunting the Eldergrove entrance itself, but far enough away that when I stayed in sneak they and Maurice managed not to see each other.

I already finished that quest without this npc, he never even approached me, so you can just kill him as others have mentioned (or let him die). However, one person mentioned that he was using an axe at one point, so maybe with a high enough pickpocket skill, you could reverse pickpocket some good armour and a weapon into his inventory?

It's far easier to get him there if you travel to Eldergrove before starting the quest, since then you can fast-travel there with him.