1) The standard mirror and screen system gives you a grainy picture with a very low ANSI CR, and a low ON/OFF CR as well. The grain of the screen adds to the film grain and looks pretty awful.
2) The flatbed scanner method. Better CR and colour reproduction, but is brutally unforgiving on dust and scrathes due to the collimated light source. A scanner using "digital ice" is the only way to go if considering this path.
3) The above option also means scanning effectively a frame at a time, or a few frames at a time. A two hour movie consists of more than 172,000 frames. So if you scanned and saved a frame every minute it would take 2,880 hours, or 360 days if you did it 8hours a day.
4) The best way would be to purchase a true telecine rig. You need something that doesn't go through condensors or screens or any other shennannigans. The DV8 sniper pro is what you would need to get anything better than what is on the laserdiscs - it can be purchased here. http://www.moviestuff.tv/dv8_sniper_pro.html. There are DIY alternatives, but at the end of the day you need quality glass lenses and a quality CCD broadcast camera ,and a modifiable Super8 projector - so it doesn't come cheaply.
You also then have to balance the exposure, do the endless scratch and dirt removal and go through and colour grade the result and do a separate sound pass - it isn't easy and is extremely time consuming, but can be done.