To load up a map with a specific gamemode through console, simply type in:
map MAPNAME MUTATION

So for instance opening up No Mercy map 1 on versus it would be:
map c8m1_apartment versus

Map names are formatted as cXmY
X being the campaign number and Y being the map number.

C1 - Dead Center
C2 - Dark Carnival
C3 - Swamp Fever
C4 - Hard Rain
C5 - The Parish
C6 - The Passing
C7 - The Sacrifice
C8 - No Mercy
C9 - Crash Course
C10 - Death Toll
C11 - Dead Air
C12 - Blood Harvest
C13 - Cold Stream
C14 - The Last Stand (ew)

Campaign - coop
Realism - realism
Survival - survival
Versus - versus
Scavenge - scavenge
Realism Versus - mutation12
Versus Survival - mutation15

Last Man On Earth - mutation1

Headshot - mutation2

Bleed Out - mutation3

Hard Eight - mutation4

Four Swordsmen - mutation5

Chainsaw Massacre - mutation7

Iron Man - mutation8

Last Gnome On Earth - mutation9

Room For One - mutation10

Healthpackalypse! - mutation11

Follow the Liter - mutation13

Gib Fest - mutation14

Hunting Party - mutation16

Lone Gunman - mutation17

Bleed Out Versus - mutation18

Taaannnk!! - mutation19

Healing Gnome - mutation20

Special Delivery - community1

Flu Season - community2

Riding My Survivor - community3

Nightmare :tomo: - community4

Death's Door - community5

Confogl - community6

RocketDude - rocketdude

Tank Run - tankrun

L4D1 Coop - l4d1coop
L4D1 Versus - l4d1vs
L4D1 Survival - l4d1survival

These were in the folder for the other mutation pictures, make of them what you will.