Okay, quick question here:

Can I complete the civil war on either side without starting the main quest?

I want to purchase the house in Windhelm, I've completed Blood on ice without a hitch and I have no interest in joining the Stormcloaks. I wanted to play through the Imperial quests to take the city and then purchase my favorite house in the game. (Before DLC adds something better) I had read something about having to start the main quest in order to do the civil war but I couldn't find anything when I searched.

I want to avoid the main quest because Skyrim is a lot more enjoyable to me when there aren't dragons swooping down and snacking on my precious NPCs.

Yes, you can. Jarl Balgruuf will still have you talk to Farengar and he'll have you fetch the Dragon Stone, but you don't have to go to Shroud Hearth Barrow or anything.

I don't mind getting it started, just as long as I don't have to get dragons to spawn by doing the watch tower section.

Just start the Bleak Falls quest and have Farengar wait for eternity. No dragons.

Hi !

I am sorry but my English is weak.
I think it is spoiler and I have a problem. I can't kill Legate Rikke she is always reborn in the Castle after conversations with Ulfric. Tullius kneels he is wounded and don't speak. Ulfric stands in an other corners in the room and do nothing. I kill Rikke but she rises from the floor and fights to me again and again.

Well yes, I know that but does the civil are require you to progress any further than that?

Nope. Dragons only spawn when you face your return the Dragon Stone to Farengar. So as long as you never pick it up from inside Shroud Hearth, you're good.

Thank you.