Car is loud when I accelerate, small single click noise when accelerating/braking. Safe to drive?

It's a 2003 Honda Accord V6 with 215k miles. The past two days it's been loud when accelerating but it can still accelerate fine (but I haven't driven over 45 mph with it like this). Also I noticed a small single click noise whenever I accelerate or when I brake. Not due for an oil change for another 500+ miles. I planned on driving it 275 miles on the highway at 70-80 mph tomorrow and another 275 back on Sunday.

Nothing to worry about or is it best to not drive that much on it?

I'm not a mechanic, but when my car was just making loud noises while accelerating, almost as if its having trouble changing gears. For me the MAP sensor was going out. Its in the shop now getting replaced.
The MAP sensor checks to see if the engine is getting enough air to change gears and other things.

It might also be the air filter itself, check and see if its clean. They are relatively cheap and easy to replace, I picked mine up at Auto Zone. I wouldn't drive it for 550 miles until the car works right again.