I've started a solo run with BG2.
Well not quite solo, I've kept Imoen with me to carry stuff.
Where can I get easy XP at the start of chapter 2, while I'm still pretty weak?
I'm a level 8 Kensai (dual in longswords) dual to mage after level 9.
The Circus tent shouldn't be a problem, where to after that?

Do all the easy stuff in the city such as the bridge district murder quest, the Copper Coronet quests, all the random battles you think you can take on (graveyard district etc). Trademeet should be pretty easy to do as well.

You can also start some harder quests and just leave them on hold if you think you can't handle it all the way through. One example would be the Unseeing Eye quest, which I believe you should be able to get to the riddling bridge at least while low level. Perhaps use an invisibility potion or spell if you want to go through areas without necessarily fighting everything.

Save up on scrolls for XP, obviously.

And if you feel the need to use an NPC to carry stuff for you, just mod a bag of holding into the game with Shadowkeeper.

Thanks Suiboon.
By the time I freed the slaves I got my fighter skills back & with Daystar +4 & Blade of Roses +3 things got a lot easier.
Gaxx is much easier solo.
The clay golems in the planesphere were a bit of a pain though.
I had Mace of Disruption +1, but with no proficientcy points in mace, I took quite a beating.
Although I think the KAI special ability might overide your lack of proficientcy.
Carrying capacity is the biggest problem & I considered giving myself a bag of holding, but I thought if you cheat, it defeats the point in doing the solo run.

It was a slog for two levels until I got my fighter skills back, but I'm really enjoying it now.
Not much harder than the team of four from my last run through.
Cloak of the Sewers is your friend.

Personally, I like doing the thieves' guild quest early.
It gives a lot of xp, lots of money to buy the stuff you need and there are no hard fights in it, except for the 2 golems at one point.

Other than that Xzar's sidequest is good too, as are any sidequests where there isn't much fighting.
I usually tackle the De'Arnise castle after that, since trolls are fairly easy to kill without taking any damage if you have a good ac, and since you have fighter levels, it can serve as your class quest.

Your main problem when soloing will be high level mages who love to cast maze, since that will result in an instant game over for some reason (apparently the game can't recognize that maze is only temporary and counts it as imprisonment).
I soloed BG 2 with a fighter/rogue/wizard multiclass, so I could backstab those pesky mages. I guess kai will serve as well if you can hit them before they activate their defensive spells.

As for the bag of holding, I don't think mods to make your life easier are really cheating, but it's your choice. If you want, you can always rush to Spellhold to get the bag there, and leave the rest of the Amn sidequests for chapter 6.