I've stayed both on and off-site, and it is definitely doable.
You should consider where you are staying, as traffic continues to become more and more congested.
If you are staying offsite, but in the Walt Disney World area, it can be really easy by car, and in fact, can be faster than trying to bus back and forth between on-site hotels and parks.
However, it can be a little more complicated if you are staying somewhere like the Universal Orlando area. It is still definitely doable, but be prepared for heavy traffic on I-4 when returning to the Parks.
You should consider where you are staying, as traffic continues to become more and more congested.
If you are staying offsite, but in the Walt Disney World area, it can be really easy by car, and in fact, can be faster than trying to bus back and forth between on-site hotels and parks.
However, it can be a little more complicated if you are staying somewhere like the Universal Orlando area. It is still definitely doable, but be prepared for heavy traffic on I-4 when returning to the Parks.