Short day (or two) trips between Amsterdam and Basel

I often drive between Amsterdam and Basel. I've started bringing my Brompton 12-speed folding bike, which I love.

I'd like to find some places to stop and do a bit of touring. Maybe part of a Eurovelo route or a short (day or two) trip. Taking the Bromoton, I can quickly jump on a train.

I'd love to hear any recommendations this group might have for one—or two-day mini adventures along the way.