Welcome back, Dave B!!! (oh, that handle is so ripe for some new rumors
)
You've gotten a lot of good advice, anything I could add would be rather redundant. Smallest character in the lead - twist, run, jump, forward - hopefully that will get you through! IF not, do not worry. The book is quoted in the BEST TIPS file so you're not up a creek. The game doesn't care whether or not you actually got/read the book as long as you know what to say when doing the ritual!
This game has a very flexible system for character development. There is no harm and often great benefit to changing class (unlike Wiz 8). It is best with magic users to get all the spells you want in the spells they are currently learning before changing class. That saves frustration later. The Best Tips thread has some useful information on all of that too!
I think it is worth while bumping sword skill up to 15. Knives and staves are the other weapons also worth improving. The game really does not favor the other weapons. I don't even bother with them anymore.
Have fun!!