At my previous company, we often did pre- and post-show email campaigns. I typically hosted all of the emails within the tradeshow program, since you can set up smart campaigns to send emails to certain lists of people (i.e. the exhibitor list). Make sure that you have reviewed your progression statuses, and that you set up the smart campaigns to acurately move them through the appropriate stages.
I set up my progression as such (for example):
1. Exhibitor List
2. Telemarketing Engagement
3. Email Engagement
4. Visited at Show
5. Engaged (success)
*We used a telemarketing team to reach out to exhibitors to generate interest in meeting at the show (in addition to email marketing).
For your purposes, I would set up several smart campaigns:
01 Pre-Show Outbound Email
Send the Email
Mark as "Email Engagement" if they click or respond, depending on your processes.
02 Visited at Show
Import a list of people who visited your booth
Mark as "Visited at Show" progression
03 Post-Show Outbound Email
Send the follow up email
Mark engagement as you like
It sounds like you might be doing direct mailing, in which case you can simply track in spreadsheets and upload to marketo in static lists, then marking their progression statuses accordingly.
Hope this helps!