bobah083- Mapstat won't help in figuring out ending score. But there is a calculator created by SirPleb that will allow you to figure this out (if you no longer gain anymore territory, population). I use his calculator as a minimum for what my score will be. It can only increase in almost all cases.
If you are anywhere near close to domination, you'll score more by delaying victory, because of all those turns at the beginning when you had little population and territory. And later in the game you have railroads and access to more luxuries (usually). If you are being crushed and losing territory so that your score is actually decreasing, then yes it may be better to lose faster.
The main fault of the game's scoring system is that it gives a bonus based on years, not turns. For example, in a recent game at the very end I was gaining 18-20 pts/turn, but was only losing out on 4 pts/turn of the early win bonus for each year I put off victory. At the highest point around the 15-1600's I was gaining 58-60 pts/turn and losing 20 pts/turn in the early win bonus. I was maxed out in population/happiness probably around this time, but my score was still going up because of the average. The other main faults of the scoring system is that it doesn't take into account map size/land available and victory condition.