Can I just include the camping gig as part of that business?
No. Your landscaping business produces "active" income; meaning that you have to go out and actually "do something" on a recurring basis to actually earn that money. So that gets reported on SCH C.
Whereas the rental business produces passive income; meaning that all you do is "sit there" doing nothing on a recurring basis to get that money. So the rental income is reported on SCH E.
Now if you develop it as campsites, then it's possible the income received from that endeavor could be considered active income and reported on SCH C "if" you supply your tenants services on a recurring basis that are "directly beneficial to the tenant". But the key is that:
1) Services provided must be directly beneficial to the tenant
2) Services are provided on a recurring basis. (What constitutes "recurring" can in some scenarios, be a grey area.)
But either way, you "generally" can't combine both endeavors into a single business because the service/product provided is not like-kind. It can get kinda complex though. For example, a business called "Wally's Burger's & Laundry Center" can provide both active income on the food side and passive income on the laundry center side. But it's perfectly possible for things to be set up so that all income is considered active income and reported on SCH C. (Not a good example really.)
