I've been watching videos of game play. Hadn't realized that some of the screens allowed only a partial "torchlight" view around the main avatar. Had to shift the map routine from straight printing of the current room, to assigning those strings to a 0-15 string array. Then I could just use MID$ to print a 5 X 5 selection of those strings around the main character. Seems to work. It has a little flicker, because I have to use CLS0 continually to erase the previous draw, but I notice that the original has a little flicker too.
Next steps will be tougher I think. I need to create routines for moving dragons and the bat around the world, even when they are not on screen, but to display them when they are in the room as the player. They'll also after to track the character in interesting ways like in the original. Here's a neat video where the Robinette (the author of the original) outlines some of his unique approaches to managing the behaviour of objects and beings in the world:
I don't know if I'll be able to recreate in BASIC all the complexity he describes without slowing player movement down to an unacceptable level. I might have to make some compromises. Perhaps more but slightly less interesting dragons (I'm thinking up to 8--one for each colour). Same for the bat. It might have to be swapped for a less dynamic random re-shuffler of objects routine, with a little stock animation. We'll see what's possible.
This kind of uncertainty is part of the charm of retro-programming in BASIC. You just never know if something is going to be possible--like the partial torch view. Feels great when you do succeed. But then again, even if you don't, this just provides a challenge for having to work creatively within the limits of BASIC. Coming up with a reasonable BASIC alternative to a faster more complex M/L routine can be lots of fun too and equally rewarding. Or sometimes not, and then one must simply learn to accept that the fun of an adventure can be simply the quest itself. How Vedantic... your have a right to your labours, not the fruit of your labours Arjuna!