CHATTANOOGA 70.3

I did Chatt 70.3 this year (and 140.6 last year) - I think it's a great race in a great community. I'll put some quick thoughts below, but you can read my detailed race report here if you want the long version.

Lodging: MANY options close to the race action, but I prefer to stay a few miles away. For both Chatt races I did, I got a super reasonably priced AirBnBs that worked out perfectly. Parking on race morning is plentiful, easy and cheap ($8 all day).
Training: The Chatt bike course is accessible and I rode it multiple times before the race. I would recommend going with others though, as many of the roads are "middle of nowhere" and if you got into trouble you'd likely want assistance. MANY groups ride from the Food City and Dollar General parking lots Saturday mornings.
Swim: Downstream and wetsuit legal this year. It's a long wait to jump in the river, I recommend bringing some sports drink to sip on. There is usually a short upstream section, but it was cancelled in 2019, making the swim short and crazy fast. 
Bike: Depends on your definition of "flat" and "hills," but I love this course. There are a few steep climbs, but lots of rollers and super fun stretches. Great crowd support through Chickamauga that will propel you back to transition. The scenery will keep your mind occupied - beautiful.
Run: Hot and some very exposed sections, but amazing aid stations and crowd support. 2 loops.

EDIT: The only concern (that's not really a concern but depends on where you live) is since it's an early season race, you may be training indoors more than a late season race, depending on the weather where you live. I felt I didn't get as many long rides outdoors as I'd normally like because of lingering cool weather and spring storms. 

I have done both the full and the half twice.  I love the bike course as there are some climbs but you are rewarded with some nice down hills.  The run has some hills, but most of the times I have raced here the temps were a bigger challenge.  Swimming is not my strength, so I like the river swim.  Even with the short up river part of the half, it is still nice to get the down river help.  Just stay close to the shore when swimming the up river part to stay out of the current. 

The community really supports this race and the aid stations are all day parties.  Really gives you a lift every time through.