Scandinavian front: Sweden successfully captured Copenhagen and even landed in Aalborg. However, with the help of Danish-Norwegian frigates spawned in the port, my few inf reinforcements managed to retake both cities.
With Frederick in Frankfurt, I manage to trade wrenches for coins which helped me to spam light arty every turn to resist Cronstedt and Sidney's bombardment.
Netherlands front/British theatre:
I spammed some line inf to defend the Netherlands from Britain's landing force, successfully stopping it.
Then, using the remnants of these reinforcements, about 3 units, I sent them to assist in the French invasion of Britain.
The London factory traded hands a few times before I captured it and held it.
Using Frederick, you can spawn and swap out wounded light arty if needed.
Do not attack Wellesley from the factory because you still need to conserve resources.
Leipzig-Drensden Line (German front):
I captured Leipzig and developed it into a formidable base in the face of the Prussian spam.
I captured Dresden early at the beginning, but due to Russian reinforcements and some troops from the Prussia, Austria and the rest of Saxony, I was blocked from advancing.
I prepared to settle in for a prolonged fight along this line and spammed line inf from both cities to do so.
I built some double stacked light arty to reinforce my troops when I had the resources and I built a fort west of Dresden to take care of attackers immediately outside of Dresden.
Early on, the enemy may capture Leipzig or Dresden using luck or they took advantage of Kutuzov's attack. DON'T PANIC.
Calmly move your troops as needed and send your arty to shell the enemy out.
Kutuzov's attack/Austria's invasion of Bavaria and Stuttgart-Württemburg:
Calmly use Frederick to trade more wrenches for coins to spawn line inf to hold Munich and Stuttgart. Take advantage of your existing fort as much as possible.
If possible, spawn some 2X light arty to help.
Kutuzov marched towards Dresden, but crossed the Danube and attacked Stuttgart alone. I spammed troops to surround him and shelled him using the fort.
However, I did not attack him with my inf until he was extremely weak.
As I still had 1 light arty left from the defense of Munich against Austria early on, so I used it to either help defend Dresden or shell Kutuzov.