The answer to "is there a better tool than the one at http://www.transhuman.talktalk.net/gt/Geosync.htm" is no.
That is not to say that it could not be improved upon by taking the output fields and converting them into fields that you can get data from, adding orbital period, and the type of stuff, but it is by far the best tool I have ever found.
You seem to have a different issue with the tool and that is, "Why is x output detail pertinent?" Those can be seperate questions and you should ask those directly. But a biref overview:
Diameter: This tells you how big or small the planet is which tells you how much surface area in total you have to work with. It also tells you how much light a planet will block when it passes in front of a star.
Density: This tells you the general chemical make up of the world is. A heavier planet needs to have a higher abundance of heavier elements such as gold, platinum, and uranium.
Surface Area: Same as Diameter really, but a calculated out amount.
Roche Limit: This tells you how close a celestial body can get without it being torn apart. If you have a moon it has to be outside this limit or it is being torn apart. I think rings are within this limit but I'm not sure.
Surface Gravity: tell you what that average gravity is at sea level
To Orbit Velocity: Tell you how fast a thing must be going to maintain orbit., ie. not fall out of the sky.
Thrust to orbit time at 3G: This tells you have fast you will reach orbital velocity starting from the ground while accellerating at 3G. It's similar to the 0 to 60 measure.
Escape Velocity: The velocity that something needs to be travel to get out of its gravity well.