@alan…
That recipe is similar to one of the oldest recorded recipe’s commonly used for small wild game (rabbit, squirrel, groundhog, etc)… Brunswick stew…
The main difference is that Brunswick stew is tomato based, instead of broth based. So you would toss in a quart of tomatoes instead of chicken broth.
One problem with either of those is the bones… you would have a finished product that not only hat the meat in it, but the bones too. Back in those days did folks have a problem with a few bones in their stew… evidently not… with the Paleo Diet it is highly recommended that you eat the entire animal, nose to tail… as we used to (on a regular basis) back before we got so highly civilized…
Organ meats are HIGHLY nutritious — there is NO veggie that even comes close to the nutritional value of beef liver. A couple hundred years ago humans regularly ate all organs, heart, liver, kidney, bone marrow, you name it, they ate it… What was left they would put in a pot and stew it and drink the broth.
When I first found my way to healing thru diet, my first step in the right direction was changing from SAD (Standard American Diet)… to Paleo Diet.
Broth based soups (Bone Broth) are highly recommended for their healing properties on the Paleo Diet… and I got really into that… and I understand how good that is for you. Thus my recommendation for broth over tomato for the base.
I make my own bone broth… and to show you how serious I was about it… I have a category on my phone (for bone broth photo’s)… probably not a lot of folks have a category for bone broth in their phone image catalog… 
I will put a image of some nice chicken bone broth below (upload from my phone shortly).
But during my 2-3 year journey thru Paleo Diet I got really into broth based soups… and some extremely common veggies to use in such soups are the trio of Onion, Celery and Carrots… they are just awesome in just about any soup or stew. Sauteed Onions, at least partially carmalized, oh so good… and add in garlic near the end of that, for even more flavor (garlic cooked too long can get bitter) so add them at the end…
Other veggies to add can be what ever you like… we don’t do potatoes (high carb) but they are awesome on most soups/stews… a low carb alternative that we often user are broccali stalks (not the florets) but the stalks, diced up, they are very good in soups/stews… and very low carb. I like to add some diced tomato near the end as well, they will cook all to pieces if you cook too long, but let them simmer in with your soup for 10-12 minutes and that works well.
And on the small game and bones… something that will help is first cook just the meat mostly, with just a little fat, long enough that it gets very tender… then take it out of our pot or slow cooker, and separate the meat and bones, add the meat and all juice back to the pot and then continue to build your soup/stew.
Veggies that are cooked in a broth based soup or stew, for 20-25 minutes will normally be cooked enough to be tender, even carrots or potatoes or broccoli stalks, if diced or sliced.
That recipe… either broth or tomato based, will make any small game animal, taste honestly about as good as they can possibly taste.
And yes, cooking longer is require for some small game, especially if they are fully grown adults, because they are just tuff.
A squirrel that is “young” can be fried like chicken, and will be plenty tender.
But one that is “old” you will wear your teeth and jaws out trying to get it chewed up.
The same is true of ground hog, coons, etc…
How do you determine if a squirrel or coon, or ground hog is “young” enough… well the way we always determine that is if they are old enough to have borne young (had babies)… they are generally too old.
If the female has suckled young, that will be obvious, if the male has well developed (specific parts)… well you know… too old for frying … better use a pressure cooker or slow cooker.
Hope this helps !
TNHunter