The constrained line drawing tool got the giant, complicated island borders drawn.  It still took a long time, but it would have been impossible the old way.

The zoomed out image looks surprisingly smooth on today's monitors, but the commodore would in reality be zoomed in on a tiny 320x200 pinhole.   There isn't much detail in each tile, but the scale was dictated by the minimum player size which could convey enough detail.  Most tiles won't have any clues to where the player is.

Color assignment is a big problem.  This world was sketched back when lion memory had 3 unique colors per cell with 1 global background color.  That was true for bitmap mode but not character mode.  Character mode allows primary colors for the foreground color & pastel colors in 3 background colors.

It seems the entire world needs the same 3 background colors.  You can't change background colors between tiles because where a background color changes, there has to be 1 tile which doesn't use the background color which changed.  Blue Max did this by only having green & brown in the border tiles.  The blue/grey color was not used in the border tiles & the border tiles ended up looking sparse.

Young lion loved light green, which costs 1 background color.  If light green, brown, grey are the background colors, the foreground has to be black, white, blue, yellow, light blue, not possible with black lines.  If black lines are taken out & the buildings are all grey, the challenge becomes just white & blue in the same cells but it looks terrible without black lines.  A raster interrupt could allow every row to have different background colors, not very useful.

There are ways to count clockcycles & change color palettes by column. Can't do anything else during the vertical scan.

If it's going to be anything close to what young lion imagined, it has to be bitmap mode.

Some experiments with loop unrolling showed it could get bitmap scrolling up to acceptable levels, but it might run out of memory or have to abandon page flipping.