//q will swap between rocket launcher and shotgun
alias rocket "slot1; r_drawviewmodel 1; cl_interp .0152"
alias shotty "slot2; r_drawviewmodel 0; cl_interp .033"
alias pick "slot3; r_drawviewmodel 1; cl_interp .0152"
alias qswitch "shotty; bind q qswitchh"
alias qswitchh "rocket; bind q qswitch"

bind 1 "rocket"
bind 2 "shotty"
bind 3 "pick"
bind q "qswitch"

//I found it much easier to set mousewheelup = rocket launcher, mousewheeldown = shotgun, and mouse3/mouse4 = melee.
// Entirely up to you though
bind mwheelup "rocket"
bind mwheeldown "shotty"
bind mouse3 "pick"