Since a Veteran can get in anytime, can his/her spouse get in with them?

Yes

Yes. The vet needs to show their military ID and can bring ONE guest with them.

Military can have one guest

The last time went with I went with my military ID I had 4 guests

Spouse of deceased disabled vet. Can I use my ID to get in and do I need to come at certain time.

Can a veteran use discharge papers in lieu of military id?

I don't know