panniers vs. trailers or both?

for panniers + rack i recommend you steel racks which you can repair in case of failure ! Everyone seems to use TUBUS racks. There are other brands of course.
Panniers also come in varied brands but most are interchangeable between different racks. You typically carry 30 to 35 kgs in the rear rack and 15 to 20 kgs in front racks (lowrider position) distributed in 4 panniers, 2 larger ones in the back and 2 smaller ones in front.

I don't have experience with trailers.

When everything is going smoothly then it is one of the best and funniest holidays you can dream of !

I've done short tours the last couple of years, towing a trailer. Next month I am going to try just using panniers and a front rack bag. It'll mean leaving some things behind that I've taken before, which is probably a good thing anyway. I'll know better in a couple of months which way is best.