If you're buying an older used van like my 2004 GMC Savana, there's a good chance your stock headlights are terrible. Upgrading them is one of the cheapest and most impactful safety improvements you can make.
If you're building out an older van (pre-2015 or so), your stock headlights are probably terrible. Older vans like my 2004 GMC Savana came with sealed-beam or basic halogen reflector headlights that were mediocre when new and have only gotten worse with age. The difference between those and modern LED replacement headlights is night and day - literally.
Upgrading to LED headlight bulbs or a projector-style LED headlight assembly is one of the cheapest safety improvements you can make. We're talking $30-80 for bulbs or $80-200 for full assemblies, and the improvement in visibility on dark roads is dramatic.
Not all aftermarket LED headlights are created equal. Make sure whatever you buy is DOT-approved or SAE-compliant for road use. Cheap LED bulbs dropped into a halogen reflector housing can blind oncoming drivers because the light pattern is wrong. If you're replacing bulbs only (not the whole housing), look for ones specifically designed for your housing type. If you're replacing the full assembly, projector-style housings give you the best beam pattern.
If you have a newer van (2016+) that already came with projector headlights or factory LEDs, you probably don't need to worry about this - your stock lights are likely fine.
Bottom line:
If you're driving an older van with dim stock headlights, replacing them should be one of the first things you do - before you even start the build. It's cheap, it's easy, and it makes driving at night significantly safer.
Light bars and auxiliary offroad lights (pods, spot lights, flood lights) are popular in the van build community. In my experience, they can genuinely be nice for rougher forest roads with hairpin turns at night where you need to see what's around the bend.
That said, a couple things to keep in mind:
If you do want offroad lights, cheap LED pods and light bars from Amazon or Vevor work fine for this - you don't need to spend $300+ on name-brand offroad lights for occasional use on forest roads.