99 Z24 - strange noise on acceleration

I have a '99 Z24, 2.4 L, with 127,000 miles. When I depress the accelerator, it starts to make a scraping grinding noise. Sounds like metal on metal, pretty much in front of the driver side. When I ease up on the accelerator it stops, and if I get the car up to speed with only a very light touch on the accelerator, it doesn't happen at all. Once the car is at any speed, including highway speed, it runs and sounds fine.

Also, and maybe related (if it's a front end issue), when I move from a stop, there is sometimes a thunk sound in the front when it first moves from that stopped position (not always, just sometimes). When a first turn the ignition key, there is a brief kind of crunching noise that immediately goes away. (Just throwing all the noises into the pot to see if any are related.) I also have a litttle bit of a squeaking noise coming from the alternator belt area, but assume that just needs a replacement and may not be related to the overall question.

I have a couple of fairly long drives coming up in the next week and am a little hesitant about the safety issues involved with any potential problems, and so wonder if potential repairs can wait a few thousand miles or if they might be an asap kind of thing.