I managed to achieve it on my warship (1000m), but I got stuck on age-old beam issue (you can "overcharge" any beam which have $fire wait: larger than certain time, IIRC it was 5).
Also, you get kills form your turrets, but it's anouther beam issue (already solved, but you must enable the fix) that prevents scoring kills even with primary mounted beams (not only for you, other ships also don't get them).
I had experienced crashes you described and FS2 Open already fixed them (I once flew Lucifer sized Warcruiser, completely without problems).
I can do fully functional capship flying for non-beam ship, it requires some heavy modding and a couple of FREDed procedures, PM me if you want more info.
Alternatively, you may try this:
http://freespacemods.net/download.php?view.524 It's a campaign demo with bonus capship flying single mission (you get to pilot Fenris there), I don't know who's the author, but he's cetrainly a FRED master, as he managed to make capship flying possible on FS2 Retail, when others couldn't do it in FS2 Open (though if you will look into mission, it doesn't seem that difficult).
This demo should function on FS2 Retail, but I had also played it on FS2 Open with mediavps.