I'm assuming those are stopovers en route?
I've stayed in plenty of Chambre D'hotes (B&B's) in those areas but if you are after really cheap I suggest using one of the big French chains such as Accor. That'll give you a choice from Sofitel/Novotel through mid range Mercures and Ibis's to budget Etap/Formule 1's (£20 per night). They have good coverage in the areas you are after and are generally situated very conveniently for getting back on your route. They are clean, cheap and for a small extra fee they'll throw in the usual French brekkie.
http://www.accorhotels.com/accorhotels/index.htmlLast time I went to Monza I pushed my budget a little and stayed at a great hotel with garage parking that is on the shores of Lake Lugano. It's about half a hour to Monza if my memory serves me right but makes a great base in a beautiful area.
Monza itself is situated in a public park. It's quite eerie filtering in to this walled, wooded park with the circuit inside it. Do yourself a favour when leaving. Kick back and relax for a couple of hours coz it's a horrendous job getting out of the place, thousands of bikes, small woodland paths you get the picture.
http://www.stelladitalia.com/htm_us/fr0_index.htmEnjoy!
