Hello
Is he and indoor or outdoor bun?
Jenson is indoor and so I put a white towels in the base (can get cheap ones in Asda). I did this because straw or hay could irritate the wound.
He'll still need hay too though so I put this in a container for him.
Packed lunch is a good idea, that way you know that the food he has is the same as usual and he'll be more tempted to eat. I packed pellets and hay. They also need to be a bit restricted for space for a bit, so he doesn't jump about too much and pull his stitches.
Hope this helps. Jenson was a bit quiet after, but was eating, drinking and pooping as normal and didn't keep licking the wound so that was all good.
Oh and like Susie says, read the section on neutering because this is just my experience with Jenson.