LOTS
COTS
COTE
CONE
NONE
RUNS --> SLOW
Runs
Puns
Pens
Lens
Leas
Lear
Fear
Feat
Flat
Flaw
Flap
Flip
Slip
Slop
Stop
Stow
Slow!
Phew. I’m sure there’s a much easier way…
COOL --> WARM
COOL
wool
wood
word
worm
WARM
VAIN —> ENVY
Impressive! I just threw it in with no solution in mind. I didn’t realize until later it would be hard.
COOL
fool
food
ford
form
farm
WARM
TINY --> TALL (There’s another with no solution in mind. I’ll retract it if I don’t get something pretty soon, or somebody else gets it.)
TINY
tint
tilt
till
TALL
I’ll leave my previous one open:
VAIN —> ENVY
Toughy. I’ll have to use some creativity here. 
VAIN
Lain
Lyin’ (Southern form of “lying”)
Lynn (As in “Bodoni”)
Lyne
Lane
Vane
Vans
Vats
Eats
Ents (More than one fictional treelike character)
Enty (“Having the characteristics of Ents”)
ENVY
Woo! Seriously, I can’t think of any way to get to “Envy,” it’s such an unwieldy word. Anybody have any real solutions?
I can’t find any step next to ENVY, nor can the old crossword-builder program I have here. How about VAIN --> HOPE?
(BTW, after much struggle, I found a shorter path from RUNS to SLOW.
RUNS
buns
bunt
bent
sent
seat
slat
slot
SLOW
(Really I eventually worked it backward. Sometimes that helps.)
VAIN
Fain
Fail
Fall
Gall
Gale
Vale
Vane
Vans
Vats
Eats
Ents
Enty
ENVY
Best I can do.
DIRK>STAB (again, don’t know if it’s possible)
VAIN
Fain
Fail
Fall
Gall
Gale
Vale
Vane
Vans
Vats
Eats
Ents
Enty
ENVY-that’s the best I can get, anyway; doubtless there are shorter ones.
DIRK>STAB
VAIN
fain
fail
fall
fill
file
vile
vole
hole
HOPE
(Yes, I used the same chain. So what?) Man, these are FUN!
I’ve read the thread title several times, and I just noticed it’s Lety’s instead of Let’s. Funny how the mind corrects stuff automatically sometimes. (This is a pain when you’re proofreading, though, especially when it’s something you wrote yourself and thus unconsciously skip great chunks of text because you know what’s there.)
DIRK
Dark
Lark
Lurk
Turk
Turn
Tern
Term
Teem
Seem
Seam
Spam
Spay
Stay
STAB
Again, there’s probably an easier way, but I like these long strings (I work stuff backwards as well). On preview I see that dwalin has already done VAIN --> HOPE, so…
CHIC --> HOBO
CHIC --> HOBO
Sorry to any who were thinking about this, but it’s addictive.
CHIC
chip
clip
clop
glop
goop
good
hood
hold
holo
HOBO
Slip>fall
Slip
Slap
Slam
Seam
Ream
Real
Reel
Feel
Fell
Fall
SOME --> MOST
some
come
came
cast
cost
most
life > burp
Whoops, jumped one:
some
come
came
case
cast
cost
most
One more and I’ll give it a break for a while.
LIFE
Lire
Lure
Cure
Curl
Burl
BURP
JOHN --> PAUL
JOHN
join
coin
coil
boil
bail
pail
PAUL
GOLD —> MINE
GOLD
mold
mole
mile
MINE
DISH → BOWL
Dish
Diss
Doss
Boss
Bows
Bowl
New one
Murder–>Redrum
Sorry - the rule is 4 letter words.
Aw, man…could a mod please correct that? I hate to typo stuff…
How about: NAME - > POST (No solution in mind)