You can't really find "Monster" cat's in those man made lakes bro. Me and my Brother caught a 40 pound Flathead in lake Havasu right in the canal where tourists hang out. If you wan't a real freshwater fishing experience then i say take the time to drive to Lake Havasu. It's about 4 hours long without traffic, 240 miles i believe. The Lake is connected to the colorado river, So you would be Catching a lot other fish then just the ones released in Lake Havasu. Here's a list of the specimens I've caught there.
LMB
SMB
Striped bass (not sure what kind but it's the trophy fish there)
Black Crappy
Carp
Flathead Catfish
Channel Catfish
Red Ear Sunfish (Found their Nesting site during the summer and we caught over 100 of them 4-8lbs each no BS Locals say it's a hybrid growing over 14 inches long)
All the other Specimens were all to small
The Stripers there get huge! I've seen pictures at the local fishing stores and they were big as the fishermens. The Scenery is beautiful, you can also rent jetskis & boat's to make the trip more epic. What me and my boys do, we go straight down there and spear them. If you have the chance to dive and go spearfishing, I highly recommend it! It's is one of the best experience in Lake Havasu for me. When you dive down Lmb's swim up to you and check you out no bs! I garuntee you will not regret the trip.