I have been taking ortho tri cyclen (ethinyl estradiol and norgestimate) for a few years. Is it okay to skip the week 4 on my current pack to not have a period on vacation next week?

Cont active pills. If a women on birth control pills wants to delay her menstrual period and maintain protection from pregnancy, she should continue with hormone containing pills from the next cycle after finishing the hormone containing pills from the previous cycle.
Yes! Its ok! Its ok if instead of taking week 4 of your current pack, you start in on day 1 of your next pack. You will probably be good for your vacation; however, don't be surprised if you have some spotting sometime before your next period. Best wishes!