Free time in Budapest - proposed itinerary

I have 4 days here between tours.  I have booked this Viator tour  for Thursday 8th Sept. Poolsuk & Val are also doing the same tour

Tomorrow, Wednesday 7th, I plan on doing a walk through the Castle area in the morning and then Margaret Island in the afternoon.

Thursday 8th, the Plains tour as above.

Friday 9th. An inner city walking tour and also a walking tour of the Jewish quarter.  I also want to check out the Gellert Hill Cave Church and will visit the Market Hall. I was there in 2013 and hope to re-visit.