Lantus is an insulin that is slowly released, and an hour or two in either direction won't make much difference. The main thing is to be consistent with the administration and when you change the schedule self-test to evaluate glucose levels.
I should clarify Option1. If your current schedule is 6pm PDT, start day 1 at 5:30pm , day two at 5pm, day three at 4:30pm, and so on until day 6 is at 3pm - 3pm PDT equals 6pm ET.
I suggest you call your doctors office for his/her suggestions since he/she knows your medical history. Here are two options you can run by your doctor:
Option 1
Start adjusting the difference in time zones a week or so ahead of travel so when you arrive at your destination you would be on your home time schedule. For example, plus 3 hrs, you would start ½ hour earlier each day for 6 days prior to leaving. When you reach your destination you would be on the same time schedule as before. Then reverse this for the trip home.
Option 2
You don't adjust ahead for time zone differences and take Lantus at the same time no matter what zone in you're in.