negotiating a lease renewal

by Corky H
(Coeur d'Alene, Idaho)

We currently have a cell tower on our property, with a 25 year lease, 10 years remaining on the lease. There is a moratorium on new sites and there are currently 4 carriers on the tower. Crown Castle bought the site from sprint. fiber optics were recently brought in. Crown wants to extent the lease and made, what I consider a lowball offer last year of $1,500 signing bonus. Now they are offering 5,000 , change the 15% increase every 5 years to CPI every year, increase the base rent $100/mo and offer a 20% co-locate for any new carriers. We are limited on excess land and not sure if there will be any new carriers. I am not sure what a reasonable monthly rent is and how much they still have on the table. They want 25 more years. How do you charge for your services. How do we get the most bang for the buck.
Corky