I 've done many many cell site searches.  I used to work for a commercial title company and they charged $75 an hr.(4 yrs. ago)  and double copy cost-it takes a lot of time to make them- & mileage.  Have to also run adjacent properties if necessary, as one has said-many times these sites are landlocked & an easement is needed over others land.  I have done cell sites from rural land to city, county and US gov't land.  It can be a mess and  usually  takes a great deal of time.  You have to be careful with the legals, especially w/out a survey.  If there is an existing tower and it's going to be subleased, you still  have to run a full on all, check for loans, liens on all of the lessees- grantor all involved, including the adjacent owners, if  the easement is needed.  They want full copies of everything. So you need to charge a pretty penny & be very careful.  Good luck.