We do loads of adult led things together. He has only just started to be coaxed into his room to play on his own, while I go and do other things. He also has his own messy play area downstairs where he can go and do stuff.
I am trying to make him more independent for when he starts school in September. Today we have been in the library for an hour and a half, had lunch, I have read to him for half and hour and now we've come upstairs. So far he's been in his room for for 20 minutes - normally he follows me around asking me to play with him.