Recommendations for tours in Savannah and Chattanooga?

Been to all those places (we live 80 miles from Savannah). You don't need a tour, do it yourself. Do your research.
https://www.tripadvisor.com/Attractions-g60814-Activities-Savannah_Georgia.html

Also, nearby Charleston, SC is a great place to visit.

New Orleans is bigger and has more concern for safety in certain areas.

I'm a long-time Chattanoogan and April is the perfect time to visit the "Scenic City". Many of our most popular sites are spread out due to the Tennessee River and the mountains (Lookout and Signal). There is a free electric shuttle that runs throughout downtown, you can park and catch it near the Chattanooga Choo Choo. In the downtown area I recommend the Tennessee Aquarium, Coker Museum (antique car collection) and a sunset river cruise on the Southern Belle riverboat. Nearby Bluff View arts district has restaurants, coffee shops and the Hunter Museum of Art. A couple of miles away is the Tennessee Valley Railroad Museum at the base of Missionary Ridge--in addition to the museum they run excursion trains and explain the history of Chattanooga as a railroad hub. On nearby Lookout Mountain are Ruby Falls (underground caves/waterfalls), Point Park (civil war battle site) and Rock City Gardens. You'll need a car to get to those places.
The only tour I am aware of is run by Chattanooga Trolley company and it gets mixed reviews.

Last year we did the Genteel & Bard Savannah History Tour which we really enjoyed. I would have loved to take their Ghost Tour as well, but we ran out of time. We also went to the Prohibition Museum that was a lot of fun.

I am normally not a hop-on-hop-off or trolley tour sort of traveler, but recently did the Old Town Trolley Tour in Savannah. I was pleasantly surprised at the good overview of the historic areas, ability to actually see from inside the bus, and the info provided. We did the entire route, noting what we wanted to return and visit on our own.

As noted above, Savannah's center is compact and is easy to DIY once you've determined what interests you.

abrinkleydc,
I haven't been to Chatanooga, but Savannah is good for two full days. New Orleans needs four full days . If in Savannah, it isn't far to Charleston SC and I recommend two full days there as well.

We did a driving tour of the south a couple of years ago. We did the Genteel & Bard Ghost Tour in Savannah and enjoyed it quite a bit. I think their historical tour would probably be good also. We also drove to Bonaventure Cemetery. I believe you can take a guided tour there which I would suggest. We spent 3 nights in Savannah which was barely enough time.

We have been to New Orleans multiple times including a week last year for Jazz Fest and food with family. Not knowing your interests, it’s difficult to recommend specific tours. In the past I have taken a cemetery tour, swamp tour, riverboat tour, National WWII Museum (which is huge and took all day), visited the zoo and aquarium with a toddler, gone to Preservation Hall with same toddler, well, you get the idea. Suggest you check out neworleans.com for ideas that appeal to you. We also rode the streetcar and used Uber and Lyft especially at night.

from 2022 - 36 Hours Savannah, Ga.

There is more to Savannah than its alluring green spaces and centuries-old Colonial, Georgian and Greek Revival architecture. In recent years, tour guides at places like the Owens-Thomas House and Slave Quarters are focusing more on the stories of enslaved people, offering visitors a fuller historical picture. Savannah is also a beacon for young creatives, thanks in part to the Savannah College of Art and Design (SCAD), and the city now has many contemporary galleries as well as newer, locally focused artist hubs like Sulfur Studios. Venture outside of the Historic District, too: In the city’s east and west, you can find a variety of Black- and immigrant-owned restaurants and bars; and the up-and-coming Starland District has plenty of attractions. But be warned — it’s not uncommon for visitors to fall in love with the city and become locals.

2 days won't scratch the surface in Charleston. I'd say at least four. I grew up in GA but there's much more to see in Charleston.

Agreed. If I had the time I would go to Charleston.

Just visited Charleston and am in Savannah. The azaleas right now in Savannah are break-into-tears beautiful. The whole city is like a garden show. Honestly never seen anything remotely like it, hope it’s still great in April for your visit.

General comment: at least when the azaleas are blooming you don’t want to stay on the river or in the not so exciting downtown. Try to stay at least 6 blocks south of the river, down to Forsyth Park.

Charleston has more history and is a much bigger city but is less charming than Savannah. Traffic is terrible in Charleston (especially suburbs) and getting to Hilton Head. I have never seen as many car crashes as I did in SC, most days we traveled we saw them.

Skip Hilton Head, no redeeming qualities.

Adding: we did better in Charleston than Savannah with respect to fine dining.

Hilton Head is fine for the beach, golf and tennis, but there's not much else to do there.

We have been to Mrs Wilkes restaurant every time we get to go to Savannah great food and experience. We also thoroughly enjoyed a morning at the 8th Air Force Museum right off Route 95 in Pooler, Georgia. You can actually see it from 95. Very well done. We did a trolley tour in Savannah and a horse drawn carriage tour in Charleston and both were totally worth the time, highly suggest it.

I second Mrs.Wilkes. Be there early as the wait gets longer as the morning wears on.