I normally leave mine loaded all season, I leave it in the case locked in my truck as much as possible WITH OUT A 209 PRIMER.
I do bring mine in and take it back out but it stays in the case when needed. I have never had a miss fire with a 209 primer, the 209s are a lot hotter and more powerful then the old #11 or musket caps. The 209s should be hot enough to overcome all but the wettest charge.
For a fun yard load I load a 350 gr Buffalo bullet with out powder and fire it with a 209M primer. This "load" will send that 350 lead bullet over 30 yards and hits my shed with enough energy to put a perfect out line of the bullets nose and as deep as the primer it's self.
If you are really worried about condensation take a FIRED 209 primer and place it in the breach plug and close the action, this will seal the charge in the barrel there will be very little air in there to cause problems.
To unload it, Just remove the 209 primer then remove the breach plug go out side and push the bullet and powder out. You will still need to clean the barrel and treads then re lube the breach plug. for long time storage a few runs with a patch and a good gun cleaner then a coat of light oil I like eezox it will not harm the powder and is a great rust preventer. If I am going to reload I just run a patch with the eezox and reload.
I always saves the sabot but get rid of the powder.