you don't ask anyone to change anything if they don't want to. you either cut is as it is and charge accordingly or just pass on the job.
this is one of the problems in lawn care. people don't seem to understand that by them having extra obstacles in their yard means that it takes longer to mow therefore raising the price you will charge them.
you can say ok $75 and if they think that is too high then you can say well i can mow it for $50 if you move that furniture and stuff out of the way before i come to mow it each time. then the ball is in their court. they can either move it, or just pay the extra cost, or not hire you.