D0 and D1 with PC level discrepencies

[Saern]

I'm planning to plug D0 and D1 into my campaign, and probably go on to run the subsequent Falcon's Hollow material as well when that's done; but my party isn't of the "appropriate" level. The PCs consist of the following:

A 4th level barbarian

A 4th level sorcerer

A 3rd level rogue

A 2nd level DMNPC bard*

This is 3.5, not PFRPG. Though some players are more experienced than others, they are all relative newbies. While, on the one hand, I think their increased level will help offset their inexperience in some of the modules' more difficult encounters, I don't want to make it a cakewalk for them. Considering there isn't a scaling sidebar, like Dungeon adventures used to have, for adjusting the adventure to characters of different levels, I'm curious what other people recommend in terms of alterations for this particular party.

I'm running these modules because 1) they're excellent and I've wanted to run them since I bought them, and 2) because my players, those rascals, have gone off the beaten path from the homebrew campaign I had planned. Those ideas will have to go on a shelf until some future time, and now I'm scrambling to provide them with replacement adventures. It's a great opportunity to plug in some of Paizo's wonderful products, but I would like to tweak them a bit so the party still has the appropriate level of challenges.

Thanks!

*

Spoiler:

I've heard it's a cardinal sin to make a DMNPC bard, but he has no ranks in any social skill; he's there for buffing, healing, and knowledge checks. I would switch him for a cleric, but the bardic music really helps them since they are far from powergamers; and bardic knowledge gives me a way to drop in story elements and background none of them would know since nobody bothered taking any Knowledge skills.