You first need to find out exactly what it is they are looking for. Mowing & trimming plus what else? You then figure out how many times for the year and multiply it to get a cost. Don't forget to figure in your costs to do the work.
When he puts in a bid for this hotel, do you think it would be better for him to walk around and come up with a bid that included different line items for each service he feels they will need? And present it to them.
Or is it better to find out what services they want first and only bid on those services?