Generate a map for a roguelike
Perl, 293 bytes

-9 bytes thanks to @Dom Hastings

{$==7+rand 30;@r=$"=();@a=((C)x4,(E)x3,("#")x1369,(" ")x1369);for$i(0..7+rand 30){$r[$i][$_]=splice@a,rand@a,1for 0..$=}$r[0][$=]=F;$r[-1][0]=P;$_=$r=join$/,$v="#"x($=+=3),(map"#@$_#",@r),$v;1while$r=~s/F(.{$=})?[^#F]/F$1F/s||$r=~s/[^#F](.{$=})?F/F$1F/s;$r!~/[CEP]/&amp;&amp;/C.*C/s&amp;&amp;/E/?last:redo}say


Add -E flag to run it:

perl -E '{$==7+rand 30;@r=$"=();@a=((C)x4,(E)x3,("#")x1369,(" ")x1369);for$i(0..7+rand 30){$r[$i][$_]=splice@a,rand@a,1for 0..$=}$r[0][$=]=F;$r[-1][0]=P;$_=$r=join$/,$v="#"x($=+=3),(map"#@$_#",@r),$v;1while$r=~s/F(.{$=})?[^#F]/F$1F/s||$r=~s/[^#F](.{$=})?F/F$1F/s;$r!~/[CEP]/&amp;&amp;/C.*C/s&amp;&amp;/E/?last:redo}say'


However, it takes a long time to run, so I recommend using this version instead:

perl -E '{${$_}=8+rand 30for"=","%";@r=$"=();@a=((C)x4,(E)x3,("#")x($v=rand $=*$%),(" ")x($=*$%-$v));for$i(0..$%-1){$r[$i][$_]=splice@a,rand@a,1for 0..$=-1}$r[0][$=-1]=F;$r[$%-1][0]=P;$_=$r=join$/,$v="#"x($=+=2),(map"#@$_#",@r),$v;1while$r=~s/F(.{$=})?[^#F]/F$1F/s||$r=~s/[^#F](.{$=})?F/F$1F/s;$r!~/[CEP]/&amp;&amp;/C.*C/s&amp;&amp;/E/?last:redo}say'


Try it online!

Explanation


{                     # enter a block (which is used as a loop)
    {$==7+rand 30;                   # randomly select the width of the map -2
                                     # (-2 because we don't include the borders yet)
    @r=$"=();                        # reset @r, and set $" to undef
    @a=(                             # create a list of the character that can be on the board
     (C)x4,                          #  4 coins 'C'
     (E)x3,                          #  3 enemies 'E'
     ("#")x1369,                     #  37*37 '#'
     (" ")x1369);                    #  37*37 spaces
    for$i(0..7+rand 30)                # create the 2D map (7+rand 30 is the height, which is generated just now)
      for$_(0..$=-1){
        $r[$i][$_]=                    # index [$i][$_] receives ...
           splice@a,rand@a,1           # .. a random character from the list previously generated
                                       # (the character is then removed from the list thanks to 'splice')
      }
    }
    $r[0][$=]=F;                       # add the finish cell
    $r[-1][0]=P;                       # add the start cell
    $_=$r=                             # here we generate a string representation of the map
          join$/,                      # join the following elements with newlines
            $v="#"x($=+=3),            # a first line of # only
            (map"#@$_#",@r),           # add a # to the beginning and the end of each line
            $v;                        # the last line of #

    1while                # the following regex will replace every accessible cell with a F
       $r=~s/F(.{$=})?[^#F]/F$1F/s  # a cell on the right or the bottom of a F cell is replaced  
         ||                         # or
       $r=~s/[^#F](.{$=})?F/F$1F/s; # a cell on the left or the top of a F cell is replaced
    $r!~/[CEP]/         # if there is no C, E or P on the map (meaning they were all accessible)
     && /C.*C/s         #  and there are at least 2 coins
     && /E/ ?           #  and 1 enemy
      last:             # the the map is valid, we exit the loop
      redo              # else, start over
}
say                     # and print the board


It takes a long time to run, because the list from which we randomly pick the characters to put on the board (@a) contains 1369 whitespaces and #, and only 4 coins and 3 enemies. So if the size of the width and height are small, there are a lot of spaces and # compared to the coin and the enemies, so it's quite likely that a random map won't be valid. That's why the "optimized" version is faster: the list from which we pick the characters is just a little bigger than the map (the list is @a=((C)x4,(E)x3,("#")x($v=rand $=*$%),($")x($=*$%-$v)) : a random number $v of # (inferior to the size of the map), and size of the map - $v whitespaces).