Welcome back to the iron, man. Muscle memory is going to treat you well, but honestly, jumping straight into 300mg of Tren Enanthate after three years completely off is playing with fire at 45. Your muscles will regain size and strength rapidly, but your tendons and ligaments haven't been under heavy loads in years. Tren is notorious for causing guys to tear things because they get too strong, too fast.
Since you already know how you react to these compounds, that's great, but you should really consider just running the 200mg of Test for the first 8-12 weeks. Let your joints catch up and re-establish your cardiovascular baseline before throwing Tren and Mast into the mix.
As for the IGF-1 LR-3, I would definitely hold off. It's an amazing compound for nutrient partitioning, but completely overkill for a comeback. Save it for when you actually hit a plateau down the road.
Finding real IGF-1 and properly dosed long esters can be a headache these days anyway. When you are ready to put your full comeback stack together, Google 10xmuscle, good people, helped me a lot with clean products that don't cause insane PIP.
Take it slow, let the joints adapt, and enjoy the comeback!
