A few lines in my vimrc for controlling the distraction-free environment Goyo.

WP Mode (Goyo)

" WordProcessor Mode / Goyo
let g:goyo_width=65

let g:wp_mode_is_on = 0

function! ToggleWPMode()
    if g:wp_mode_is_on
        set formatoptions=tcq
        set nowrap nolinebreak expandtab
        silent! nunmap <buffer> k
        silent! nunmap <buffer> j
        silent! nunmap <buffer> 0
        silent! nunmap <buffer> $
        silent! iunmap <buffer> k
        silent! iunmap <buffer> j
        silent! iunmap <buffer> 0
        silent! iunmap <buffer> $
        let g:wp_mode_is_on = 0
    else
        set formatoptions=ant1
        noremap k gk
        noremap j gj
        noremap 0 g0
        noremap $ g$
        set wrap linebreak nolist noexpandtab
        set formatprg=par
        set spell spelllang=en_us
        let g:wp_mode_is_on = 1
    endif
endfunction

nnoremap <Leader>g :Goyo<CR>:call ToggleWPMode()<CR>