Going on a week long trip to Tampa area. Do I need to flush with fresh water every night or just when I put her on the trailer at the end of the trip? Anything else I should know?

I would think that a 1 week stay wouldn't require a daily flush and that a thorough flush at the end of the week on the trailer would be fine.
If you intend to do this in the future on a regular basis, I would suggest installing a Neutra-Flush system.
I'm sure others with more knowledge about this subject will give you more advice.

Is your engine raw water cooled? If so, any aluminum components like intakes? If you do I would give it a quick flush every day.

Do you have fresh water fittings? We make a couple trips in salt a year, flush every night, wash the entire boat down in the morning and evening. I also use CRC to spray the engines and wiring down. I will also run it in fresh water when I get back to get all the salt out.

raw water cooled with no aluminum...100% stock 454 mag. A "T" and two ball valves in the waterline that goes from the transom to the impellar would allow me to flush in the water.

raw water cooled with no aluminum...100% stock 454 mag. A "T" and two ball valves in the waterline that goes from the transom to the impellar would allow me to flush in the water.

What year 454 Mag. Mine is a 1990 and came from the Mercury factory with a aluminum intake. Better double check that. Either way if you can flush daily I would.

+1

If I were you I would flush after every single use. It's just not worth it to chance it. Salt is some nasty sh!t!!! Oh and CRC is a must too!

Here use this. Low cost, simple to use and removes salt from motors and boat exterior.

http://www.saltawayproducts.com/

Its salt not acid,flush if you can run the boat in fresh water for an hour when you get home clean it good and no one will never know.
As for aluminum I rebuilt a Jet-Ski engine after 10 years of only salt use.They have almost all aluminum engines and manifolds,there was no corrosion at all. So in my opinion aluminum holds up better than cast iron.