Ivy,
I owned a 280C for 16 years. If it was a hot day and heavy, I would wind the rpm up to full, lean off the mixture to 130 pounds at 36.5 inches of manifold pressure and cushion creep slowly out into the wind. Do not lean any more as your EGT would go too high and you would loose power. Very easy to over pitch, so listen to the engine revs as you go. Check your oil cooler is not caked up with old oil and there is no grass stuck in the vent.
In the cruise I would reduce rpm to bottom line and lean off to 85 pounds per hour fuel flow at 29 inches, watching EGT. with this I would get an endurance of 2.6 hours.
You can fit tubes in the tyres, they should be hard, 50 ppsi at least. If you buy some locally and keep them for spare in case you over inflate the old cracked up ones.
The Enstrom is a lovely bird and I have never felt safer in any other machine.
Have fun.