Are you going to do any races besides the Memorial Park races?
The order I did things when coming up cat5 was:
Off the front (not a serious attack, since I didn't know any better)
Crash - you've already gotten this one out of the way.
Breaks will be incredibly difficult in the cat5 race at Memorial Park. If you want to try that, organize it BEFORE the race. Talk to the people you want, decide when and where to meet and attack. Make sure they have teammates to block and that their teammates know the plan. I've got some experience with this, and no one will bridge if you go solo, they will only reel you back in > then you'll be tired. Keep in mind that the average speed of the race is ~26 mph, so if you want to stay off the front, you'll have to manage probably 25 mph for however long you wanna stay off (assuming someone is blocking).
Each race dedicate to a specific skill you want to develop.
Race 1: Attack near the end of the race - maybe 2 laps left. Use your computer's lap function and time how long you stayed away. This is knowledge you can use later when you want to win. Did you get separation? You'll go OTB after a real attack, don't sweat it.
Race 2: Go for all the primes - this will likely put you OTB. That's OK. practice positioning, figure out how far you need in order to wind up your sprint. I learned way way late in the game, that I have to have a long distance to wind up, I can't just pop it like the typical "sprinter"-type.
Race 3: Practice bridging. Let a guy/group get 5 seconds on the pack, attack up to him. You don't have to work with him, just get there. Rinse and repeat... make sure you don't drag the field.
Race 4: Leadout/finish - get to the front with 1 lap left, this is a skill in and of itself - top 3/4 positions. If you can do that and feel good, maintain your position and try to sprint.
Anything you're going to do at the end of the race (1,4), do it during the weeks that's cat5 only. Anything during the race (2,3), do on the weeks that its a 4/5 race.
These are just ideas, but they're probably good goals/practice. I'm sure others can think of more. I raced almost that entire series last year and didn't have real goals for any of the races, so you're on the right track.