"... Should I go measure the property even though it will take forever? ..."
Not to be critical or harsh, but if this is your approach to this sized job, perhaps it is not one you should be attempting to land. Even if it takes you two hours to measure off, and get it right, the two hours will be trivial if you ignore measuring, and estimate the job 30 minutes short for each visit.
There are online tools for property measurements that are very accurate, and cost nothing. But, if you not willing to invest some time in a good estimate, them maybe you are stepping into a hornets nest that will sting you in the end.