Brandon Hughett has given more information on a alternate put-in for Crab Orchard.
Here is the link to the webpage
(During Closed Hunting Season)
Okay put your thinking cap on and get out your Tennessee Gazetteer.
Leaving I-40, take the Westel Road exit. Head north. At mile 1/2 you will come to an
intersection. GO LEFT. Drive about 5 miles
Once into/at the Catoosa Management sign, head left....I SAID LEFT! Pay attention I hate
telling someone to use a sign, when a redneck might shoot it , or steal it.
The put-in fords the creek.
(During Open Hunting Season)
find Catoosa Road ,leaving Wartburg Tennessee, then once driving, you will come across Nemo Bridge.
Drive across Nemo.Leave Nemo bridge and continue driving on Catoosa Road. At the Catoosa Checking
station take the fork in the road, to the left. Then in a little bit you will drive by Island Creek.
You will cross Island Creek. Keep driving, keep driving and you will come to Crab Orchard.
Put-in #3 -Alternative from Brandon Hughett via Facebook.
The put-in mentioned above talks the about Catoosa Wildlife Management Area being a factor and some ridiculous shuttle through Nemo.
Plus, the put-in mentioned above suggests adds several miles of flatwater to the run. The run is already long, I'm not sure why you'd want to add flatwater to it.
TWRA has a designated put-in with a concrete boat launch at Flat Rock Ford which will put you in about a mile or less above the good stuff.