Vibration at 2800 rpm 1st, 2nd and 3rd

I have a 2000 Accord SE AT i4 (4-cyl) 180k miles. It is my daughters car and I don't want to waste any of her money as she is paying for it, so I am resisting just changing things without being as sure as possible. From a stop, especially when going up hill, there is an annoying amount of vibration in the dash that seems to get more pronounced as the engine revs higher and then peaks as the engine gets to about 2800 rpms. After shifting into the next gear, the vibration goes down but then begins to climb again with the climbing revs. When the car is in park/neutral at 2800 rpms the problem isn't there. Some vibration of course but much less vibration. Also, at highway speed it runs very smooth (the rpms are about 2200 at 60mph so maybe not a good test). If you think it might be an engine mount, I am curious which one you think it is. There are 4 on this model (front, back, right (actually the AT mount) and left (locations are from the drivers perspective). The mounts visually look fine, nothing broken and no significant cracks, but they all might be 16 years old now so... Is it more likely to be the transmission mount because the vibration seems to only happen when the transmission is engaged/the car is moving? Suggestions on how to test the mounts - remove for closer inspection or? If you say CV axle, would all of the symptoms I mentioned be explained by CV axles? If so,which one is it more likely to be right or left, or is it both? I looked at both and visually both look fine- the boots are in good shape at least. There are no funny sounds upon turning sharply either, and again, the vibration goes down, while accelerating, when the car shifts gears, so it seems less likely to my small brain that it is CV axles but then again I don't know much. I've spent a lot of time trying to logically figure this one out as you can tell and I would be grateful for some experienced advice before proceeding

My brothers Acura CL vibrated under heavy acceleration due to the CV's and it went away as load goes down. For the mounts have someone sit in the car and hold the brakes, put it in gear and rev the motor up (but don't stand in front) you should be able to see which mount has a significant amount of movement except for the lower ones. If the motor don't move much your mounts should be ok. I don't know if there is another method peeps use this is how I have always done it.