Hey Hippowhurr, got the pm ^_^ Anywho, I like the team, as well as the way it uses Unburden Hitmonlee well, the core of Unburden 'Lee+CB 'Tomb is a pretty cool one I've personally toyed around with myself a little :P
Anywho, as you mentioned, the Regenerator Grass-types seem somewhat difficult to play around, being resilient to Pursuit trapping attempts, continuing to check the majority of your Pokemon to an extent. Moreover, I can see a well-played Entei, Choice Band variants in particular, being a major issue for your team, having access to a powerful Extremespeed to check Hitmonlee with, as well as a strong Flare Blitz, which threatens your entire team to an extent as your Lanturn takes a hefty 40 - 47.16% from it. Lastly, Kabutops carrying Waterfall can really put a dent in your team, as it can threaten to pick off Hitmonlee after enough residual damage, can outspeed and 2HKO your primary switch-in's to Water-types with Life Orb-boosted Stone Edge, and can even play around Spiritomb's Sucker Punch by merit of Aqua Jet.
That in mind, I don't feel as though Accelgor is the best choice for this team. "Lead" Accelgor functions best in a very offensively oriented team, where the player can immediately apply offense pressure to prevent spinners from removing them and of course take advantage of aforementioned Spikes for breaking through Pokemon, whereas this team appears much more balanced overall. In this type of it team it only puts more pressure on Spiritomb to block Rapid Spin without greatly achieving its primary objective of a Hitmonlee sweep. I would reccomend that in its place you try
Mixed Druddigon. Druddigon not only offers your team an alternative response to Entei, but also an excellent lure for Tangrowth, who is promptly 2HKOed by a Sheer Force-boosted Flamethrower. Here is my proposed set:
...

Druddigon @ Life Orb
Trait: Sheer Force
EVs: 152 HP / 252 Atk / 20 SAtk / 84 Spd
Brave Nature
- Outrage / Dragon Claw
- Flamethrower
- Earthquake
- Sucker Punch / Substitute
To elaborate, the given EV spread seeks to maximize overall bulk and Attack, with enough Special Attack to consistently OHKO standard Escavalier after Stealth Rock damage, and enough Speed to outpace minimum Speed Tangrowth.
With this change Rotom-C's necessity to take on Grass-types attacks and other such specially oriented assaults is starkly reduced. That said, I feel as though your team might function more fluidly if you ran a
Choice Scarf variant over your current set. This change would allow you to take on Kabutops and other physically oriented Water-types better, while providing a moderately fast scout and revenge-killer as well. Additionally, this change would offer you a utility in the form of Trick, which allows it to cripple walls attempting to switch in on Rotom-C, such as Amoonguss and Tangrowth. For reference, here is the set:
...

Rotom-Mow @ Choice Scarf
Trait: Levitate
EVs: 252 SAtk / 4 SDef / 252 Spd
Modest Nature
- Leaf Storm
- Volt Switch
- Trick
- Hidden Power [Ice] / Thunderbolt
tl;dr:
That being said, I hope that my comments were of use to you, good luck in the future ^_^