An foldable guide for a continuous rod injector features first and second segments of similar length and a shorter third segment. In a fully folded state of the guide, the shorter third segment is foldable into a position contained between facing-together concave sides of the first and segments for improved collapse of the guide into a compact state for storage or transport. A proximal end of the first segment is mounted to the injector, which is carried on a mast having a selectively deployable jib thereon at an elevation above the installed position of the injector. The jib is movable between a slant-mode condition reaching outward from the mast and a vertical-mode position retracted into a more compact relation with the mast. The slant-mode condition provides improved support and stability by providing a more direct overhead support for the rod guide in slant well applications.