Assuming you'll be using the same hotel before and after your flight, I'd use the roller suitcase and bring along a backpack for the trek. I've bookended a trip with stays at the same hotel, so I just have them keep my suitcase in storage until my return. If you're staying at a decent hotel, you won't have any problems.

That way your business wear will be in decent shape, and you'll still have the flexibility of the pack for your adventure.