Mini Pumps For Roadbike (120 psi)?
A longer frame pump is advantageous - a lot of them can be mounted along the length of your top tube and work a lot faster/easier than mini pumps. Mini pumps (and frame pumps in general) always take forever (at least, it feels like forever, though some are better than others due to chamber size and if they can inflate on the push and pull stroke of the pumping action among other design factors) and are tough at higher pressures. You just need to get enough air until you can get to a track pump - In theory and by design, you could probably get to full pressure with a good frame/mini pump but in practice, you may not due to tired-ness and other factors that come with a ride. The amount of time and effort it takes obviously depends on the volume of the tires and pressures you're running as well as how quickly you can pump. If you look at some reviews, you can probably find the highly variable measurement of how long someone took to pump their tire in "pumps". 

When you use a hand pump like a conventional frame/mini pump, you lose the advantage of weight and upper body muscles you use with a floor (track) pump (aside from the typically smaller volumes) [but you can get this on the go to some extent with a frame-mounted floor pump]. The Lezyne Micro Floor Drive HP-HPG looks interesting as a small frame-mounted floor pump (similar to the Topeak Morph line, but oddly much cheaper and possibly more ergonomic) and according to a review does quite well on the pressure and inflation efficiency front. 

I don't think a gauge is necessary, but a hose is useful - you avoid transferring your momentum of pumping directly to the valve, which can cause some damage if you do it too much (i.e. not careful). Sheldon has some tips for doing this (my current frame pump does not have a hose, but I do wish it did). 

If you do get a mini pump though, try to get one with a CO2 inflator built in as well and carry some CO2 cartridges (or at least a mini inflator). Some day you may be too tired or in need of a quick inflate (e.g. in the rain), and this could really help you (though they can't do minor adjustments of a tire pressure like a pump can).  Also, try to avoid flats in the first place - kevlar belted tires, proper tire inflation, etc. will save you the agony of having to use your pump. And always have a way to get home otherwise (e.g. bus, calling someone, etc.).