Wow it was 170,000 still left in the field? I had no idea it was that many. I understand that the Army of Northern Virginia was the main Confederate forces but with that many men still under arms Im surprised the other armies surrendered so easily. I had been under the impression that all the Southern armies were in similar conditions as the Army of N. Va.
Your impression is basically correct Harris the figure of 170,000 is a rough estimate by some historians but how many effectives is another story and the possibility of any substantial armies joining together was simply not viable. Plus from March through to April '65 the desertions from the Confederate Army were wholesale and unstoppable.
I haven't got all the facts but I do know that Lee surrendered just over 28,000 effectives at Appomattox. Joe Johnston's Army of Tennessee had approx 34,000 when Sherman resumed his march northwards on the 10th April. Johnston followed him having no illusions about being able to stop 80,000 Union troops marching through NC unopposed (he was definitely no Bobby Lee). Whilst en-route he learned of the evacuation of Petersburg and the surrender of Lee's army at Appomattox. This brought an end to any hope of joining the two armies together to either defeat Grant or Sherman.
Others that come to mind:-
Dept of Alabama, Mississippi and East Louisiana under the command of Lt Gen Richard Taylor surrendered over 14,000 troops on 4th May.
Confederate District of the Gulf commanded by Gen Dabney Maury had also attempted to join Johnston's army after retreating from Mobile but after JJ's surrender he followed suit the next day surrendering 10,000 effectives.
Dept of South Georgia & Florida under MG Sam Jones surrendered 16,000 troops to General McCook at Tallahassee, the only Confederate state capital, east of the Mississippi that was not captured by military action.
Thompson's Brigade in Arkansas under Meriwether Thompson surrendered 9,000 efffectives at Jacksonport.
Gen Wofford surrendered 10,000 men at Kingston GA.
And it's also worth remembering that most Southern states had State & Militia troops normally under the command of the State Governor for example Georgia had 20,000 such troops that were surrendered by the Georgian Governor to the Union Army.
The other substantial Reb army was the Trans Mississippi Dept under Lt Gen E. Kirby Smith he had a little under 30,000 troops and he continued to resist following Lee and Johnston's surrenders, decrying all Confederate deserters with the threat of them being shot if caught. He travelled with an entourage to Houston with plans to rally the Texan Confederates to join his army and continue the struggle. When he arrived he learned that Lt Gen Simon Bolivar Buckner had surrendered the army during his absence. This didn't stop this old warrior and he led 2000 ex-Confederates into Mexico with grandiose plans for the Confederacy to rise again but slowly over the following months this rag-tag army dissolved (Incidentally this episode was the basis of the 1964 Hollywood movie "Rio Conchos").
I haven't done the math to the above and there were many many other smaller detachments such as Mosby's Cavalry who surrendered their sabres following the capitulation of the main Confederate Armies.
One interesting fact that you may or may not know is that the Confederate States of America were never formally surrendered. The States, Armies, forts, warships etc of the Confederacy all surrendered over a period of time and Jeff Davis captured and made a prisoner of war, but at no time was the Confederacy as a whole country surrendered and I believe that to be still extant today.
Reb