generator just to charge batteries

Sounds like overkill for battery charging only. It's NOT the quietest generator in the campground nor is it the most reliable (at least mine was not in either case) but it WILL do the job with a little tinkering from time to time.

I definitely would consider a quiet model such as a Honda. With our 35 foot fifth wheel we carry along a Honda 2000. It's perfect for charging the batteries while dry camping or boon docking and just watching TV. I rarely run the MW when dry camping, but if I need to, I can with the eu2000. You may say you won't be running the AC or MW now but you may end up doing just that. If you can swing it, buy the 2000 at minimum. The 1000 may be too small. I agree with you on the AC though. For all the years we've been dry camping, we've never run the AC but most of that, if not all, is done at 6600' +

Don't do it! (The Champion, that is...). They are obnoxiously loud, especially in a quiet campground. Might be OK for a NASCAR race, or for truck-stop dry camping, but questionable elsewhere....

If you are absolutely SURE that you wont need A/C or microwave, you can likely get by with one of the small Yamaha's or Honda's... about 1000W. If you have any interest in running either the A/C or the microwave, then start to look in the 2400W range....

A little off-topic for your request but: How big is your battery bank? If you are just looking to charge batteries you might want to consider adding solar. Once installed it is automatic and no maintenance. If you have just a single battery then 100Watts solar would likely do the trick and you can self install 100Watt for $200

Reliable? Don't know what you'll get for 200 but can't be much. I like the Onans. They are quiet and reliable and you can buy them on Ebay fairly cheep!