I had the joy of the Lydd NDB 21 on my initial IRT (in a G1000 equipped airframe). I was allowed to use GPS guidance to ROMTI as long as it was single needle tracking (and with moving maps disabled) -- using pure NDB/DME you'd presumably have to route to LZD first as you can't guarantee RNAV through old-school point-to-point nav to LZD 331(?)/4.4...