I did all the side quests (except Mind Flayer lair in the sewers) with my own solo sorceress

Not so tough. Just try to gain as much XP as you can, buy the robe, find some cool rings. By the end of stronghold quest I usually become of significant power. And after all trademeet trouble I get lvl8 spells. And after unseeing eye quest I am a god
I still insist on sorc having some decent INT&WIS score. Its just an image of trully powerful spellcaster - he/she must be veery intelligent&wise. That's rp, man!
CON score is nearly useless - if enemy gets to strike you you're dead no matter what is your CON. Spellcasters do not participate in melee crap - they stand back and rain death on the heads of their enemies
DEX is nearly useless for the same purposes. Why should I care to use a sling when I have Melf's Minute Meteors for nearly endless missile weapon? And when you grow a bit, say, older

you wont have to use any sling or such - your spells will be your best weapon. The best and the only one
All this discussion makes me want to solo a sorc once again - this time, a CE one