Spiders on the Storm (11 pages, at DriveThruRPG) is a fun fantasy adventure for Fifth Edition D&D, but I used A Dungeon Game (50 pages, same place). I used GEMulator as my solo engine. I created five first level characters. Each had one spell, two weapons, and no armor.

So, the first thing the PCs had to deal with was a nasty storm. My undertaker character took damage from the mudslide and then died drowned during the flood. When they arrived at Archway, they had to deal with two giant spiders. My gambler character got bitten twice and died because of the poison. The other three PCs did kill one of the giant spiders. The other one was hit with a beast friend spell and it retreated. At this point, Tulak joined the group (he had been living at Archway). He was the one that had the antitoxin potions. The PCs then tracked the spiders back to their den. In the den, they had to fight two giant spiders and an Ettercap. Shea the astrologer went down because of two spider bites. Tulak healed her and cured her of the poison. The loot was pretty good. They found copper, silver, electrum, gold, three potions, and an oil of slipperiness. Give this RPG a try!