Great day out
Abdelkarim was very knowledgeable and a great person. He's been a guide for many years (since the late 1980's) and he does tours around the world. You can ask him deeper questions about Carthage and he'll be happy to share more. I watched a really nice overview before going and it helped me connect more deeply with what I was experiencing and gave great conversation topics: https://www.youtube.com/watch?v=6dbdVhVSat8.
He has a lot of stamina, so you'll want to try to keep up (with the correct footwear) :-). To be fair, he asked if his walking was too fast multiple times, but we wanted to get some exercise.
By nature, Ancient Roman Carthage is quite spread out. You'll take a taxi from the "colosseum" area to the baths. From the baths you'll typically walk to the ancient Carthaginian port, but you can also take a taxi.
We would 100% recommend doing a tour with him.