Practice Fields and Indoor Practice

We have a total of 8 fields at our complex. One for tee-ball thru 8/9, one for 11/12, one for 13/14 and one the high school plays on. We also have 4 softball fields for girls softball and adult softball. The recreation department will not let you practice on the fields. They state and probably correctly that they can not maintain the fields with that amount of use. Therefore, we have to practice on the elementary school playgrounds. These "practice fields have a back-stop, no bases, no mound, no fence, no lines. How would you conduct a practice at this type of facility. Thanks.