Good luck with the titling process. I can't help with Illinois but when I titled a trailer in MT with only a bill of sale I found that my local DMV either didn't know or wasn't able to research. I ended up having a few conversations with the state office that oversees the locals and they were able to help me out. At least they told me what to tell the local office to git 'er done.
I just went to the secratary of state and they just gave me paperwork for Titles obtained by Bond - just glancing over the forms - they want cash (a bond) 1 1/2 times the appraised value for three years in case of any lien. Is there and easier way to get title with a bill of sale? they seem to require - bill of sale, written appraisal, cash bond, application fee and of course tax fee - dang !!
I also had to get my trailer appraised. I took it to the local RV dealership and they took one look at it and appraised it for $100. Our state didn't require a bond if it the appraisal was less than $500.
I don't think bonds are that expensive, though. Check with your insurance agent.