On my 98 Honda Accord 6 cyc. all dashboard lights will flash on for a second or two while driving and then go out. It happens intermittently. Car and all accessories work fine. Alternator was replaced recently. I need to make a 400 mile trip on Monday. Is it safe to drive?

. Test and charge the battery. I would remove and fully charge the battery. Most auto parts stores will test and charge batteries for free. I'd have this done, prior to making the trip.

. Test the alternator, even though it is new (rebuilt?). The symptoms, that you described, are like an alternator that has worn brushes and dirty slip rings. If you installed a rebuilt, I would exchange it.

Another possibility is that the dash dimmer control has a worn spot. Move it from left to right both extremes a few times.