Where to stay
There are some accommodations in Szarvas, including hotels with Spas and swimming pools (https://maps.app.goo.gl/RhPmWyU7jrZULSebA), summer houses along the Körös river, and some hotels.
We're also looking at arranging some basic accommodation in a student residence which is very close to the wedding's venue. Please let us know if you're interested in this option.
One possibility is to stay in Budapest, but please be aware that it takes at least 2,5-3 hours to arrive to Szarvas by car. And sometimes it's worse with traffic.