https://public.nrao.edu/event/vla-spring-open-house-2/2019-0...
https://public.nrao.edu/event/vla-spring-open-house-2/2019-0...
The Trinity site was compelling from a historical standpoint but it's really just a patch of desert in a missile range. There was small tent set up with information in addition to the markers. Most of the time for the experience was waiting in a car on a road in the middle of nowhere and speculating about occasional bits of debris in the distance.
Both are worthwhile but I'd go for the VLA.
Other than that the exciting time is when they are moving the dishes (they are on tracks, and they move the dishes closer together / further apart). I'm trying to look up the dates, but I can't find them on their calendar now.
That said. The Trinity site is some plaques, a shack and New Mexico scrub land; the VLA is (if in a close configuration) a dramatic sight, some plaques and New Mexico scrub land AND if it's an open house: the chance pick the brains of operations people.
That's the big difference, open house VLA you can talk to people who's lives are the VLA; Trinity you can talk to people who volunteered to keep tourists from doing anything stupid.
My first visit to NM was on an ISEF-sponsored trip in 1983, when the science fair was held in Albuquerque. We didn't visit the Trinity site (or at least I didn't), but we got to play with a CO2 laser at Sandia Labs, chill out on the couches encircling the Cray 1 at Kirtland AFB, and watch the NMIMT 'Terminal Effects' group blow some stuff up in the desert. (Un)fortunately the demo was conducted with conventional explosives only, but it was still fun to watch.
There was also a gigantic wooden trestle spanning a canyon in the same area, wrapped in giant Helmholtz coils for testing aircraft under various EMP conditions. I imagine that's all done via simulation these days.