things absoultly needed to beat the game:
pray (to get silver horn and for the final event)
silver horn (to get by the snake
level 5 (to get a pirate ship
cards (lov sol moon death)
mark of force snake (you can get away with not getting force but 3 of your charecters will die in the final palace)
you CAN via a little known glitch sneak into the final castle without the horn or mark of snake.
with luck manipulation you can do it i'm sure
one of the time gates go to the final island on the side of the river. if you manipuate luck just right you can have a pirate ship spawn in just the right spot.
this happened to me once in the years i've played it (I promptly died in the final area and lost the ship sadly)
my suggestion would be like this:
cleric wizard wizard wizard (if you want to get the force mark otherwise its really up to you but make sure you have a charecter who can use cleric and wizard spells to level up to 5 quick)
level up to 5 (manipulate fights as to always fight 8 undead for 32exp per fight)
go to yew, get pray(lots of fire panels, may need to use heal carefully again manipuatling the rsults as to get more hp per use)
get a ship, go in whirlpool
get the 4 cards in ambrosia
die (fastest way to get back to lord british)
manipulate luck to get on the final island (pirate ship trick)
with carefull dodging you CAN avoid all the dragons in the last castle
a good trick is to go to your status screen right before a dragon touches you when you return your 4 charecters will be on one tile and you can avoid many attacks)
defeating the invisible tiles will be a trick since you're at such a low level with minimal spells, but thats the only really tough fight, and again you can just manipulate luck to not die here.
use cards (love sun moon death)
get the ankh
get the hell out of there :-)
your toughest challenge is beating the two pirate ships (manipulate luck to get the least amount of pirates on each ship, possibly buying a few ands of time would help drasticly)
defeating the "floors" will be tough too since you can't stop time here again manipulating misses and hits will help, might want a fighter charecter or maybe a ranger just for these few fights since you won't be spending much (if any) time in dungeons so no magic is needed really
edit1: I tottally forgot, you can't fight in the final palace without the silver weapon, might want to use more wizards and use thier lower level missle/flame spells to defeat the floors
edit2: note all of this is from memory..
I beleive there might be two spots in the final palace where the force barriers are in your way..so the trick of having 4 people run across them and having one survive isn't going to cut it.
what i'd suggest is to get the 4 cards on ambrosia, get a flower give it to sherry, then go to the closest dungeon with the mark of force, desend/sink to it ,grab it fast and use the compass heart to get out fast, then continue with my little walk through :-) (since you won't have enough mp to rise back out or cast surface the heart is the best bet...my memory on the dungeons is a bit hazy, might want to check maps and see the easiest force mark to pick up .