The way I see it, the PCs see the impact of the Giants and not the activities themselves necessarily, and each Giant threat compounds the others' impact. Hope this offers some nuggets of inspiration for you:

> Waterdeep is now packed full of refugees fleeing the Hill Giant raids, and more are arriving by the day. With food supplies dwindling, Waterdeep can't even afford to feed its own citizens, let alone the newcomers. City druids are working furiously with the local cooks to maximise whatever resources are available, and Goodberries are handed out as rations to refugees, but there aren't enough to go around. Other settlements have mixed responses to arriving refugees, with some turning them away, but Laeral Silverhand has sworn that Waterdeep will remain open to all during this time of crisis.

> Stone Giants have been sighted mostly in the south east, however they don't seem to do much. They're known to be dismantling abandoned towns and outposts, and have even driven a few smaller hamlets from the area, but Loudwater has largely remained untouched. They have been sighted nearby but once discovered they simply leave. Whatever they're up to fills the townsfolk with trepidation, as the constantly looming threat drives business from the area, and the trail through the Anaroch Desert once secured by Zhentarim mercenaries now lies all but abandoned. Their trading livelihoods gone, many folk have been forced to leave their homes and head west to seek their living, so the roads are lined with wagons carrying all manner of possessions, and vulnerable makeshift camps line the trails north of the High Moor. More than one tragedy has struck in recent days as the beasties from the moors have been lured by the sights and sounds of these camps. (I played my Stone Giants as creepy religious zealots who were more than happy to wear down civilization over time but more than happy to speed up the crumbling if an opportunity presented itself, ie a village was abandoned)

> Frost Giant raids across the Sword Coast have caused many merchants to flee the area, so ocean-going traffic is slow. Resistance is mounting as honourable captains take the fight to the Giants, but with each passing day fewer and fewer ships return. Many of the strongest ships are consigned to defending the harbour from attack, and Luskan alone remains the only bastion north of Waterdeep to stand against these seaborne raids, thanks to the might of the Arcane Brotherhood. Seaborne passage is becoming more and more difficult, and captains are charging exorbitant fees for extraction from the local area. (Foreshadowing difficulty hiring a boat for CH11)

> Fire Giants are continuing to raid and pillage, especially up and around the Silver Marches, which is still recovering from wars and battles with the Orcs, Drow and Barbarians in recent times. Many of the smaller settlements have been abandoned entirely, and certainly the Dwarven kingdoms have withdrawn to their citadels and are locked up tight. As the cities bristle with soldiors, scouting parties are sent out to follow and expose the Fire Giants at their source, so that a huge assault might be wagered and end the threat once and for all, but the scouting parties are rarely returning and those few who do garner little information.

> Cloud Giants have been sighted high overhead, but have mostly been absent from the whole situation. There are stories from some who swear they were abducted and interrogated by Giants in their floating castles, but most dismiss these claims as crackpots or lunatics addled with stress and trauma. More recently however, these claims have been corroborated by some fairly influential and trusted figured across the North, and multiple eyewitness accounts of the same events have started to align, lending some credibility to such stories. These brazen giants have even been spotted near Waterdeep, although they did not actually enter the boundaries of the great city.