Hi Derek,
I have attached a script. Drop it in your ~/.coot-preferences directory and restart your Coot. Should work (not tested). If you want a specific mtz file, then you will have to use x-n-open via Calculate -> Scripting -> Scheme.
Paul.
;; return a list of map numbers (define (x-n-open mtz-file-name) (map (lambda (col-pair) (make-and-draw-map mtz-file-name (car col-pair) (cadr col-pair) "" 0 (caddr col-pair))) (list (list "2FOFCWT_xray" "PH2FOFCWT_xray" 0) (list "FOFCWT_xray" "FOFCWT_xray" 1) (list "2FOFCWT_neutron" "PH2FOFCWT_neutron" 0) (list "FOFCWT_neutron" "FOFCWT_neutron" 1)))) (if (defined? 'coot-main-menubar) (let ((menu (coot-menubar-menu "Neutron"))) (add-simple-coot-menu-menuitem menu "Quick-load MTZ" (lambda () (x-n-open (most-recently-created-file "*.mtz" "."))))))