There's a few things that that I am counting on to make ToB doable.
1) my armor class isn't affected by my low level, and you already have something like 1/2 the hp of a fully leveled character by the time you're at 7. So my melee survivability won't be affected as severely as one might initially fear. Of coure I also lose out on hardiness, so probably I will be only be living for ~1/4 as long as an equivalently equipped high level character. I'm hoping that this is still enough for me to be able to do some damage while having time to heal myself in between (with potions or rod of resurrection if I really need it).
2) Speaking of damage, probably the single most important difference between a lvl 7 vs high level warrior aside from HLAs is the thac0. This means that thac0 boosting equips are super important for this run. Fortunately most enemies don't actually have very good armor class so this isn't usually even an issue. In SoA the only things that are seriously hard to hit are dragons, and these I've taken care of by using strength boosting potions + potion of heroism/power + berserk. In ToB, BEFORE any of the hard fights, I get to pick up the answerer which should solve my thac0 problem for the rest of the game with it's +2 AC penalty on each hit. One thing I'm unsure of is whether this effect works when you hit a stoneskinned opponent. That could make a really huge difference in the final battle since iirc Mel spams stoneskin a lot., and I have no way of getting rid of it other than whacking them.
3) On a related note, I will be missing greater whirlwind, which means that I have to work a bit harder to get decent DPS. The plan is to used improved haste (bracers of blinding strike, gaxx, improved cloak of protection) together with belm in the off hand and some long sword in the on hand. I have ***** in longswords and * in two-weapon style, so this gives me 8 attacks per round at +2 thac0 (plus offhand which basically never hits). Due to the crappiness of most enemies AC this is enough to give very reasonable damage output most of the time. Only in cases where I already have really hard time hitting my opponent does the thac0 penalty matter, and for those fights I will normally need a shield equipped to stay alive anyways.
4) Finally, there's my saving throws. These are somewhat lackluster, and I expect this to be the biggest source of trouble in ToB. I'm hoping that a combination of every layering every single save boosting item I can get my hands on + berserk immunities + equip-specific immunities will be enough to get me through. berserk already protects me from everything I can think of except blindness and save-or-die. I can also equip various weapons in my off-hand to protect against everything except those + stun and maze. I can switch between these in combat too, so they need not interfere with my offense in any serious way. Once I get Hindo's Doom +4 I will be able to equip death ward at will so I won't have to worry about insta deaths anymore either. Edit: I forgot about the fact that I also have potions that grant huge save bonuses, so this probably won't be an issue anyways.
I'm also somewhat concerned that ToB fights will tend to last longer than my more short-lived buffs, but I will deal with that issue when I come to it.