If I might suggest as somebody who had to disregard everything Japanese political sources tell me - do NOT look information inside Japan. Europe and USA both have extensive experience in these matters, the level of knowledge there is much higher. They do not need to be here in order to know better. Both European and US nuclear scientists publicly suspected meltdown when it was actually happening, instead of after several months like their Japanese counterparts. This is a recorded fact. Also, every radiation peak in Kanto area was predicted 12 hours before by combination of American weather data and SILAM simulations done by the
Finnish Meteorological Institute (and several others, but I used this). All the peaks were confirmed by
KEK institute at Tsukuba. Japanese politicos (government, local governments, Tepco, NISA, Tokyo University) revealed nothing during all this time.
About what you asked:
you would probably be OK. You could get good connections as a foreigner who came to Fukushima during this time. The background radiation is 20x normal, but the smallest recorded radiation dose linked with cancer is 100mSv, and that would take about 10 years to accumulate with the present rate.
You would have to eat contaminated food "for the benefit of the local economy" or some crap like that. You would get cell damage, but those cells would die off anyway in about three months, which is their normal life span. Damage to DNA would not be so severe with such a low dose rate, so the regenerated cells would be healthy anyway. Body can fix all but the most severe DNA damage before cell division, so your future kid would probably have all fingers and toes. Unless you're the kind of Japanophile who prefers tentacles. Which might be a bit difficult to guarantee, though.
Gamma radiation from Cesium penetrates everything but the heaviest lead sheets, which is actually good news. Because of the penetration ability, there is 99% chance it won't even notice you while going through you without interacting in any way with your cells. Other radiation types (alpha, beta) are more interactive. But because of just that they can be blocked with, for example, a sheet of paper or a layer of air more than 10cm (4"). Neutron radiation is not good news, so avoid field trips to Fukushima nuclear plant in the next... 40 years or so (Chernobyl is 25 years and still going hot, so no quick fixes for Fukushima, either).
You would accumulate radioactive iodine (type beta) in your thyroid, creating a local radiation hot spot in your throat. Trust me, you don't want that. You might want to consider bringing food/spice products that contain clean iodine (I have not nor will ever recommend iodine medication, that stuff is way too concentrated). You would need a daily dosage of about 150 micrograms of iodine to keep your thyroid happy.
Radiation sickness and damage is NOT contagious. No more than an knife wound is. However, radioactive dust may transfer from clothing to clothing. If you're not in the habit of taking daily showers and using clean clothes, get one.
Wear a mask when it's especially dusty outside, wash your hands and face when coming inside, don't eat dirt, don't play in radiation hot spots, all that... Basically, increase and maintain your personal hygiene levels. Which is always a good idea in all occasions.