axolotl

If none of you speak any Spanish, it would definitely be difficult. As for safety, Chile felt like just about the safest place I've ever toured. Argentina isn't particularly unsafe, especially rural Argentina. But the economic situation there is chaotic right now, which could make the country a bargain, but could also have some less pleasant ramifications for visitors. If you want a real adventure, look into the "Carretera Austral" in southern Chile. Most of my biking in both countries was the the lake & volcano region between Puerto Montt & Temuco in Chile, and near Bariloche, Argentina. The Andes are low there and were easy to cross.

I would seriously consider northern Thailand in that period. You don't have to bother with camping gear or stoves because good, inexpensive accommodations, and delicious inexpensive food are readily available. Thailand has the best value for money of anyplace I've visited. Weather is ideal at that time (generally highs in the low 80s, lows in the 50s from Dec-Feb). The scenery is nice, people are friendly, and roads are pretty good. Enough people speak basic English that language wasn't a huge issue. Northern Laos is good too, though in villages, accommodations can be much more basic (though cheaper). Language was sometimes an issue in Laos, but a phrasebook and a friendly smile worked fine. You can either fly into Chiang Mai or take a train with your bike from Bangkok. There's also a train to Vientiane, Laos, from Bangkok.