DOSBox
I run WC1 at 3,000 or 3,300 cycles. Even 4,000 - which I think is the default for the GoG installation - is too fast for me.
Control
No questions, the mouse controls in the early Wing Commanders are badly implemented. Like -danr-, I've always played with keyboard, and I find WC1 (including the difficult SM1 and SM2 missions) playable. WC2 is more of a problem, with its faster ships and more evasive AI.
Asteroids
Asteroid fields in WC1 are malicious. Those rocks aren't floating in space, they're thrown towards you at speeds proportional to your own. As Whistler says, fly at 250 kps, 300 maximum. Go a little bit faster, and you'll find the oncoming asteroids are much faster. Afterburn, and you'll find one impacts you in about three frames.
Later in the game, you'll face asteroids with Kilrathi in them. You generally can get away with higher speeds and sharper turns in these, but don't get careless. The rocks are often more of a threat than your enemies' guns.
Minefields
Mines gradually drift towards you, but don't usually get in your face the way asteroids do. I usually just set top speed and afterburn in a straight line. You'll occasionally take damage, but usually not through shields.