I think that it is wonderful that you are working to proactively manage a very difficult situation. I imagine it must have been very disappointing to hear about the budget cuts, but I think that you are taking the right steps to ensure that your son still gets the benefit of social experiences and learning.
 
I recommend that you schedule short play dates (for short attention spans), inviting three or four other children. I would plan a combination of structured and unstructured play dates. For instance, one week you may choose to have a structured play date at your place. Another week, you may want to schedule the play date on the playground to incorporate more unstructured time. Structured time is great because children learn how to take turns and sit still, which is good practice for kindergarten. Unstructured time is important, as well, because children can exercise their imaginations muscles.
 
For ideas to incorporate play and fun, take a look at some of the preschool activities offered on this site:
 
http://www.education.com/activity/preschool/
 
Finally, for additional ideas, take a look at the two articles below regarding play dates.
 
Best wishes,
L. Compian, Ph.D.
Child Psychologist
Education.com