What is a good leveling path for the new 100 heroics?

From a different post, the new level 100 Heroics should have gear similar to Tier 1 RoF group armor. What would be the best leveling and gear path to get to the current expansion? Or is it pretty simple to just go through the expansions one by one starting with RoF?

Is there any content that should be avoided as it is relatively too hard for the reward? I seem to remember TBM content has issues.

Depends on your goal. Is it to experience content or to get to max level asap? Things like grinding Gribble HA in dead hills can level you fast

do the expansions Mercenary and Partisan quest that have a major exp boost for finishing

If it's anything like existing 85 heroics, you will need to grind augs and spells a zone back or so to be even mildly useful at a player. Tanks especially come out so hilariously under geared it's barely worth boosting.

The 85 Heroic tanks that got plopped into HoT content were insane for that content. Granted, moving from HoT into VoA or RoF left something to be desired, but for HoT T1 and T2, there was no fear of dying (unless you did something like pull 8 mobs).

We’ll have to see what it’s like for the tanks in RoF gear

Personally I'd forget RoF and go straight to CotF. Start at the camp in Ethernere with the vendors and work the heroic missions there for currency to get augs. It will also get your started on earning Heroic AAs.

Work through the progression, no one should miss the completion of the Dead Hills part. I won't ruin it for those who have never done it before.