I'd walk to the Contemporary and take the bus from there. The bus stop is between BLT and the CR tower, very easy to get to via the MK walkway.
I'd probably allow 90 minutes from walking out of MK to getting to Raglan Road, since you have to walk from MK to the bus stop (10-15 minutes), wait for the DS bus at CR (the least predictable portion of the trip), ride to DS and then walk to Raglan Road. You might be early, but to me that's better than being late!