Can some one help with home office and business miles questions?

I have a room in my house where I repair items that I later sell at a flea market. I also use this room to store these items and other items that I sell at the flea market.  I use this room almost every day for those purposes; and this room is not used for anything else. I have some questions:

1) Can this room be considered a home office so that it can be used to show a home business expense on schedule C?

2) When I go to the flea market, two to four times a week, I leave from my home. Can the mileage to and from there be ‘business miles’ that can be deducted?

3) Some days, either before or after going to the flea market, I stop at resale stores, like Goodwill, to buy items to fix up and resell. Some of these shops are just off the route I take to the flea market; each maybe only 1/ 4 to 1/ 2 a mile total. Other shops are further away, ie past, the flea market. Would the mileage to these ‘further away’ shops be ‘business miles’?

PS: I have a construction job, with a W-2, where most of my income comes from; but if the weather is bad I do not work.

This is new schedules and calculations for me.

Thanks for your help.