I might have forgotten to mention an xp update.  Hopefully you've been keeping good track of your xp expenditures, because I haven't.<br/><br/>Also, the main bonus for really hard DCs for tumble checks is your ability to add skill ranks and skill boosts to things.<br/><br/>At any rate, remember that you can go through with aid another checks and readied actions to cast hide undead on characters that flub their rolls, which makes things a little easier.  (If you set up a marching order and establish you're all going as a team, you can go ahead and roll other players' aid another checks, though each failed check will inflict a -1 penalty)<br/><br/><br/>Though of course, blast your way out is another option.  The movements of the undead make it pretty obvious where intelligent undead are moving, so I'm not even going to bother having you guys do anything to avoid them.