And if all else fails, I really don't think average sunscreen would have much risk at all... If you're going to be in the sun all day, the danger of sunburn and heat exhaustion is probably higher than the risk of chemical absorption and damage from one sunscreen application. But if you're going to be in the sun for moderate, safe amounts of time but just want an everyday sunscreen to protect your skin, then maybe it's worth getting something more natural and chemical free...
There's some pretty expensive organic, all natural ones out there with bases like almond oil etc (maybe try a health food shop? Or online) and a zinc cream/stick would be fine too (but gross for a whole body covering).