We are taking our old landlord to court in Illinois but live in Texas. Can we add our travel expenses to our small claims suit?

You can try, but absent a contract or statute which provides for the prevailing party to have his legal fees and expenses reimbursed by the loser,, each side pays their own.  However, if you are suing your landlord under your lease, you need to review it; leases generally contain attorneys' fees provisions.