Hah! Great minds think alike! I too am just now replaying JA2. This is my first time on the 1.13 patch though and it is quite different from what I remember. I'm playing on expert with very good selection at Bobby-Ray's, save anytime, scifi on and vanilla (old-school) inventory.
I went with 4 initial mercs. My IMP, Buns, Igor & Blood (could only afford Blood for 1 week). My IMP is high agility, mech, marksman, health & decent strength with both special abilities spent on sniper. In hind-sight, I should have gone either both lockpick, or maybe lock & electronics.
My initial strategy was to head straight for Drassen, avoiding any encounters I could by either avoiding the roads or trying to sneak past 'em. I still had to fight 1 or 2, but got to Drassen Mine relatively unscathed. I took that by using the roofs and doing a couple of pin-->outflank manoeuvres. I then used my new income to train up some militia and then repeated the process on the middle section. In hind-sight, I should have taken only the mine & airport, but hey. I didn't take the last Drassen sector as that would have triggered the massive backlash and I wasn't ready yet.
Instead I took off and repeated my previous tactics on Chitzena (far west town), taking the mine first, training militia. This time I used the 20 blue militia to help in the invasion of the top sector (man, this is an awesome addition to the 1.13 version), as I only had a couple of longer-range rifles and the soldiers hiding behind the middle wall can sometimes cause me issues. Trained the remaining militia, fought off a small counter-attack and headed back to Drassen with the two American tourists in tow. I left Ira behind to finish the militia training.
Landed back in Drassen, made sure the militia on the two lower sectors that I owned were up to scratch and then took the airport. This is when it got tricky. Taking Drassen triggers off the queen sending a good 60-odd soldiers (including quite a few elites) to re-take the mine. There's no point in trying to train more militia while they are en-route as they arrive too quickly.
Instead, I move all of my militia to the top two sectors, leaving the mine empty. The soldiers move in and I attempt to retake it with the help of my best militia. I do it this way (instead of defending the mine) because otherwise my militia are spread all around the map and basically get picked off one by one. As soon as I took the airport I went straight to bobby-ray's (which became available at this point) and ordered up 3 high-powered sniper-rifles and a FN-FAL with the money I've produced from the mines thus-far. I wait until my new toys arrive, equip them and head on down to the party...
And run into a brick wall. My party can now pick off enemies in one shot from the rooftops quite well, but my 20 non-elite militia are rubbish and can't survive long enough against 60 combatants (I don't expect much, do I?), so pretty soon I'm dodging burst fire from all sides & pinned down.
I'd read lots of accounts of people hiding in toilets, etc, but I wanted to win this "straight-up". I tried several times before I decided to be a bit more devious. I noticed on the map that not all of the 60-odd enemies would fit in the mine sector itself. Only 20 are allowed per sector so the rest were camped east, west and south of town. If I try to attack the mine they are called on as reinforcements and arrive part-way through the battle, eventually swamping my position.
Instead I took my 4 mercs and attacked the enemies camped to the east and west alone. Each camp held about 15 individuals, but with my superior sniping equipment they were a cake-walk compared to the mine. I took each camp out, taking time to rest & re-arm between sorties and this reduced the total enemies by ~30. At this point I marched back into Drassen Mine like before and had little trouble painting the town red.
Besides taking a SAM site to the east, getting some more stuff-that-goes-bang & a new merc, that's pretty much where I'm up to now. Alma, here I come! :D